זרעים
הלכות מעשר שני ונטע רבעי
פרק ח

Halacha

הלכה א
הַלוֹקֵחַ בְּהֵמָה לְזִבְחֵי שְׁלָמִים וְחַיָּה לִבְשַׂר תַּאֲוָה מִמִּי שֶׁאֵינוֹ תַּגָּר וְאֵינוֹ מְדַקְדֵּק יָצָא הָעוֹר לְחֻלִּין. אֲפִלּוּ הָיוּ דְּמֵי הָעוֹר מְרֻבִּין עַל דְּמֵי הַבָּשָׂר. אֲבָל הַלּוֹקֵחַ מִן הַתַּגָּר לֹא יָצָא הָעוֹר לְחֻלִּין:
כסף משנה
1.
When a person [used money from the second tithe to] purchase a domesticated animal for a peace offering or a non-domesticated animal for ordinary meat from a person who is not a merchant and is not precise, the hide is considered as ordinary property.1I.e., the sacred quality of the second tithe no longer applies to it. It is as if the seller gave it to him as a present.
In his Commentary to the Mishnah (Ma'aser Sheni 1:3), the Rambam explains that when a seller is not meticulous in his business dealings and thinks that he sold only the meat and does not think about the hide, none of the money of the second tithe was used for the hide. Hence, the hide is considered as ordinary property.
This applies even if the value of the hide is greater than the value of the meat. When, by contrast, a person purchases an animal from a merchant, the hide is not considered as ordinary property.2For a merchant is careful about getting a full price for his merchandise and will make sure to include the value of the hide in the price. Since the person will be using the money from the second tithe for the purchase, that purchase will also encompass the hide. Hence the hide is considered as the servants and land mentioned in Chapter 7, Halachah 17, and one must eat an equivalent amount of food in Jerusalem. Although ordinarily, one may not purchase non-food items with money from the second tithe, in this instance, an exception is made, because the meat cannot be purchased without the hide. See Radbaz.

הלכה ב
וְכֵן הַלּוֹקֵחַ כַּדֵּי יַיִן סְתוּמוֹת מִמָּקוֹם שֶׁדַּרְכָּם לְהִמָּכֵר סְתוּמוֹת מִמִּי שֶׁאֵינוֹ תַּגָּר יָצָא הַקַּנְקַן לְחֻלִּין. לְפִיכָךְ צָרִיךְ הַמּוֹכֵר לִפְתֹּחַ רָאשֵׁי הַכַּדִּים כְּדֵי שֶׁלֹּא יֵצֵא הַקַּנְקַן לְחֻלִּין. וְאִם רָצָה לְהַחֲמִיר עַל עַצְמוֹ וְלִמְכֹּר בְּמִדָּה יָצָא הַקַּנְקַן לְחֻלִּין:
כסף משנה
2.
Similar laws apply when a person purchases jugs of wine that are sealed.3But not while they are open as the Rambam continues stating. In a place where it is customary for these jugs to be sold while sealed from a person who is not a merchant, the jugs are considered as ordinary property.4I.e., like the sale of the hides mentioned in the previous halachah, when an ordinary person buys or sells wine, he does not take the value of the jugs into consideration. For the container is considered as subservient to the wine it contains. Indeed, the flavor of the wine is somewhat dependent on its container. Accordingly, the two are considered as a single entity. (See Eruvin 27b which derives this concept through Biblical exegesis.) Hence, the money of the second tithe is not used for the containers. Therefore the seller must open the tops of the jugs so that they will not become ordinary property.5By opening the jugs, the seller indicates that he desires to consider the jugs independently [the Rambam's Commentary to the Mishnah (Ma'aser Sheni 3:13)]. By opening a jug, the seller indicates that he wants the purchaser to pour it into his own containers. If the seller wishes to be stringent with himself and sell the wine in exact measure, the container is considered ordinary property.6Since he is selling the wine at an exact fee per measure, he is not including the price of the jug in the price of the wine (Kessef Mishneh).

הלכה ג
לְקָחָן פְּתוּחוֹת אוֹ סְתוּמוֹת בְּמָקוֹם שֶׁדַּרְכָּן לְהִמָּכֵר פְּתוּחוֹת. אוֹ שֶׁלָּקַח מִן הַתַּגָּר שֶׁמְּדַקְדֵּק בִּמְכִירָתוֹ לֹא יָצָא הַקַּנְקַן לְחֻלִּין. לָקַח סַלֵּי תְּאֵנִים וַעֲנָבִים עִם הַכְּלִי לֹא יָצְאוּ דְּמֵי הַכְּלִי לְחֻלִּין:
כסף משנה
3.
If he purchased [the jugs of wine] while they were open7As mentioned above, opening the container is an indication that the container should be considered as an independent entity. or sealed in a place where it is customary to sell them open8Since it is customary in this place to sell the containers open, even if one sells them while sealed, he is considered to have followed the general practice of considering the container as a separate entity. or he purchased them from a merchant who is precise in his sale,9Following the same reasoning as in Halachah 1. the jugs are not considered as ordinary property. If a person purchases baskets of figs and grapes together with their container,10I.e., the basket. the container is not considered as ordinary property.11For the fruit is sold independently of the baskets (Radbaz).

הלכה ד
לָקַח אֱגוֹזִים וּשְׁקֵדִים וְכַיּוֹצֵא בָּהֶן יָצְאוּ קְלִפָּתָן לְחֻלִּין. לָקַח חוֹתָל שֶׁל תְּמָרִים יָצָא הַחוֹתָל לְחֻלִּין. קֻפָּה שֶׁל תְּמָרִים אִם דְּרוּסוֹת יָצְאוּ הַקֻּפּוֹת לְחֻלִּין. וְאִם לָאו לֹא יָצְאוּ לְחֻלִּין:
כסף משנה
4.
If a person purchases nuts, almonds, or the like, the shells are considered as ordinary property.12For they are obviously secondary to the fruit within them. Even a merchant is not concerned about them. Hence, one may benefit from them without worrying about purchasing their worth in food to be eaten in Jerusalem. If a person purchases a frond of dates,13The dates together with the branches from which they are suspended. the frond is considered as ordinary property.14Since the dates are crushed, the container is obviously subservient to them, for they could not be sold without it. Hence, it is not considered as a separate entity.
[The following rules apply if] one purchases containers of dates. If they are pressed, the containers are considered as ordinary property.15For the containers are considered as subservient to the dates. If not, they are not considered as ordinary property.

הלכה ה
מִי שֶׁהָיָה לוֹ יַיִן שֶׁל מַעֲשֵׂר שֵׁנִי וְהִשְׁאִיל קַנְקַנָּיו לְאוֹתוֹ מַעֲשֵׂר. אַף עַל פִּי שֶׁסָּתַם אֶת פִּיהֶם לֹא קָנָה מַעֲשֵׂר אֶת הַקַּנְקַנִּים. כִּנֵּס הַיַּיִן לְתוֹכוֹ סְתָם אִם קָרָא שֵׁם וְעָשָׂהוּ מַעֲשֵׂר עַד שֶׁלֹּא סָתַם אֶת פִּיהֶם לֹא קָנָה מַעֲשֵׂר אֶת הַקַּנְקַנִּים. וְאִם מִשֶּׁסָּתַם פִּיהֶן קָרָא שֵׁם וְעָשָׂהוּ מַעֲשֵׂר קָנָה מַעֲשֵׂר אֶת הַקַּנְקַן. הִפְקִיד לְתוֹךְ הַקַּנְקַן רְבִיעִית חֻלִּין אוֹ שֶׁכָּנַס לְתוֹכָן שֶׁמֶן אוֹ חֹמֶץ אוֹ צִיר אוֹ דְּבַשׁ שֶׁל מַעֲשֵׂר שֵׁנִי סְתָם בֵּין מִשֶּׁסָּתַם בֵּין עַד שֶׁלֹּא סָתַם לֹא קָנָה מַעֲשֵׂר אֶת הַקַּנְקַנִּים:
כסף משנה
5.
When a person has wine16As opposed to other liquids as indicated by the conclusion of the halachah. from the second tithe and he lends17We are speaking about a person using his own jugs. Nevertheless, the term "lends" is used because the person desires to retain possession of the jugs as ordinary property. He is merely "lending" them temporarily to be used for the second tithe. In his Commentary to the Mishnah (Ma'aser Sheni 3:12), the Rambam writes that the person must make an explicit statement of the above intent. his jugs for that [wine from] the second tithe, the second tithe does not acquire the jugs, even though he seals them.
[The following laws apply if] he stored the wine in them without making any statement:18I.e., he stored wine from which the second tithe had not been separated in jugs and then desired to set aside several jugs as the second tithe. This reflects a reversal of the Rambam's understanding in his Commentary to the Mishnah (loc. cit.). The Radbaz explains, however, that the two rulings are not contradictory. If he designated [certain jugs] as the second tithe before he sealed their openings, the second tithe does not acquire the jugs.19Thus after the wine is poured out from them, he may use the jugs as ordinary property, without any further measures. If he designated [the jugs] as the second tithe after he sealed their openings, the second tithe acquires the jugs.20For the wine and the container have an integral relationship as mentioned above. Indeed, our Sages compare it to separating wine in its jug to separating fruit in its peal. Thus if the value of the wine is transferred to money, the value of the jugs must also be included (Radbaz). Nevertheless, if one drinks the wine, the jug is no longer considered as consecrated to the second tithe and may be used for other purposes (Rambam LeAm). If [the owner] stored a revi'it21A measure of 86 or 150 cc depending on which Rabbinic authority one follows. of ordinary wine in the jug,22By putting ordinary wine in the jug, he indicates that he does not desire that the jug be acquired by the second tithe. or put oil, vinegar, brine,23I.e., brine that was purchased with money from the second tithe. or honey from the second tithe without making any statement - whether before or after he sealed [the jugs] - the second tithe does not acquire the jugs.24For in contrast to wine and its containers, the containers of these liquids are not necessary for the liquid itself and are always considered as separate from them.

הלכה ו
צְבִי שֶׁלְּקָחוֹ בְּכֶסֶף מַעֲשֵׂר וּמֵת יִקָּבֵר בְּעוֹרוֹ. לְקָחוֹ חַי וּשְׁחָטוֹ וְנִטְמָא הֲרֵי זֶה יִפָּדֶה כִּשְׁאָר פֵּרוֹת שֶׁנִּטְמְאוּ. הַמַּנִּיחַ דִּינַר מַעֲשֵׂר שֵׁנִי לִהְיוֹת אוֹכֵל כְּנֶגְדּוֹ עַד שֶׁיֵּצֵא לְחֻלִּין וְהָיָה הַדִּינָר יוֹצֵא בְּעֶשְׂרִים מָעָה. אָכַל עָלָיו בְּעֶשֶׂר מָעָה וְהֻזְּלוּ הַמָּעוֹת לְאַחַר זְמַן וַהֲרֵי הַדִּינָר יוֹצֵא בְּאַרְבָּעִים מָעָה צָרִיךְ לֶאֱכל עָלָיו בְּעֶשְׂרִים מָעָה וְאַחַר כָּךְ יֵצֵא לְחֻלִּין. הוּקְרוּ הַמָּעוֹת וַהֲרֵי הַדִּינָר יוֹצֵא בְּעֶשֶׂר מָעִין אוֹכֵל עָלָיו בְּחָמֵשׁ מָעִין וְאַחַר כָּךְ יֵצֵא לְחֻלִּין:
כסף משנה
6.
When a deer that was purchased with money from the second tithe dies, it should be buried with its hide.25Since the animal was never eaten, the hide is not considered as a separate entity. Thus since it and the animal are consecrated with the holiness of the second tithe, they must be buried. The deer may not be redeemed, because "we do not redeem consecrated entities in order to use their meat to feed dogs [the Rambam's Commentary to the Mishnah (Ma'aser Sheni 3:11); Hilchot Issurei Mizbeiach 2:10]. Rabbi Akiva Eiger questions this ruling, citing sources which indicate that in similar circumstances, the hide can be considered a separate entity and should be redeemed. If it was purchased while alive and slaughtered and then it became impure, it should be redeemed like other produce that became impure.26See Chapter 2, Halachah 8; Chapter 7, Halachah 1. Needless to say, this same law applies when a person purchases meat and later that meat becomes impure (Radbaz, based on the above mishnah).
[The following laws apply when a person] sets aside a dinar of money of the second tithe to purchase food against until he has exhausted its value and it becomes ordinary funds27In other words, the person set aside money that was consecrated from the second tithe. Nevertheless, instead of using that money, used ordinary money with the intent that the holiness associated with the second tithe is transferred to the ordinary money as that money was spent to purchase food. [and then the value of the coinage changes. For example,] the rate of exchange for a dinar was 20 me'ah.28The Rambam is obviously speaking in hyperbole. The ordinary exchange rate of a dinar is six me'ah (Hilchot Eruvin 1:12). The person consumed ten me'ah's worth of food and then the value of the latter coinage decreased. Afterwards, the rate of exchange of a dinar was 40 me'ah. The person must spend another 20 me'ah on food before [the dinar] is considered as ordinary money.29I.e., he must use half a dinar for food. Now, however, the value of that half a dinar in me'ah has doubled. The rationale is that the value of the coinage from the second tithe is calculated at the time and place it is transferred.
If the value of a me'ah increased and the rate of exchange for a dinar was ten me'ah, he must spend another five me'ah on food. Afterwards, [the dinar] is considered ordinary money.30Again, he is using half a dinar, but now the value of that half a dinar in me'ah has been halved.

הלכה ז
הַלּוֹקֵחַ פֵּרוֹת בְּסֶלַע שֶׁל כֶּסֶף מַעֲשֵׂר וּמָשַׁךְ הַפֵּרוֹת וְלֹא הִסְפִּיק לִתֵּן הַסֶּלַע עַד שֶׁהוּקְרוּ הַפֵּרוֹת וְעָמְדוּ בִּשְׁתַּיִם. הֲרֵי זֶה מַפְרִישׁ עֲלֵיהֶן סֶלַע בִּלְבַד שֶׁנֶּאֱמַר וְנָתַן (אֶת) הַכֶּסֶף וְקָם לוֹ. בִּנְתִינַת הַכֶּסֶף קוֹנֶה. וְהַשָּׂכָר לַמַעֲשֵׂר:
כסף משנה
7.
When a person purchases produce with a sela of money from the second tithe and draws the produce into his domain, but did not pay for it before the value of the produce increased and it became worth two selaim, he is required to pay only a sela for the [produce]. [This is derived from the phrase]:31The Rambam's wording has attracted the attention of the commentaries who note that there is no Biblical verse which uses that exact wording. See Leviticus 27:19 which uses somewhat similar expressions. "And he paid the money and it was acquired by him." [Implied is that the produce] is acquired by paying money.32The Rambam's wording has attracted the attention of the commentaries. Seemingly, the reason for the Rambam's ruling is that once the purchaser performed meshichah, he acquired the produce. Hence, when he pays for it, he pays the price at the time of its acquisition. This is not implied by the Rambam's wording. Indeed, as the Ra'avad emphasizes, the Rambam's wording implies the very opposite. The profit is realized by the second tithe.33I.e.., he must eat the entire amount of produce according to the stringencies required of produce of the second tithe. One might think that the purchaser would profit from the rise of the value of the produce, i.e., he could eat half of it as the second tithe and use the other half as his private property. Hence, the Rambam clarifies that this is not so. The Radbaz explains the Rambam's wording, explaining that the transfer of the holiness does not take place until he pays the money, but that afterwards, the produce is acquired by the second tithe according to its price at the time of acquisition.

הלכה ח
מָשַׁךְ פֵּרוֹת בִּשְׁתֵּי סְלָעִים וְלֹא הִסְפִּיק לִתֵּן הַמָּעוֹת עַד שֶׁהוּזְלוּ הַפֵּרוֹת וְעָמְדוּ בְּסֶלַע אֵינוֹ מַפְרִישׁ עֲלֵיהֶן מִמְּעוֹת מַעֲשֵׂר שֵׁנִי אֶלָּא סֶלַע אַחַת. וּמוֹסִיף עָלֶיהָ סֶלַע שְׁנִיָּה מִן הַחֻלִּין וְנוֹתֵן לַמּוֹכֵר. וְאִם הָיָה הַמּוֹכֵר עַם הָאָרֶץ הֲרֵי זֶה מֻתָּר לִתֵּן סֶלַע שְׁנִיָּה מִמְּעוֹת מַעֲשֵׂר שֵׁנִי שֶׁל דְּמַאי. נָתַן לוֹ סֶלַע שֶׁל מַעֲשֵׂר וְלֹא הִסְפִּיק לִמְשֹׁךְ הַפֵּרוֹת עַד שֶׁעָמְדוּ בִּשְׁתַּיִם. מַה שֶּׁפָּדָה פָּדָה וְהַדִּין בֵּינֵיהֶן:
כסף משנה
8.
If he drew the produce into his possession when it was worth two selaim, but did not pay for it until the value of the produce decreased and it was worth only a sela, he should pay only one sela for them from the money of the second tithe. He must add another sela from ordinary funds and give it to the seller.34I.e., since he drew the produce into his possession when it was worth two selaim, he must pay that amount to the seller. Nevertheless, he may not pay that entire amount from the money of the second tithe, because now the produce is not worth that amount. Indeed, if the purchaser would give the seller the second sela from the money of the second tithe, the holiness of that money would not be transferred to the produce and the seller would be obligated to use it to purchase food which he would eat according to the stringencies of the second tithe. If the seller was a common person, it is permitted for him to give him a second sela from money from the second tithe of demai.35In his Commentary to the Mishnah (Ma'aser Sheni 4:6), the Rambam explains the rationale for this ruling. Since we are speaking about demai, there is only a question if there is a prohibition involved. Accordingly, since a common person is more lax in his observance and will violate even more severe prohibitions, we assume that he is not precise in his observance of demai. Hence, it can be given to him. The commentaries question that explanation, for even though he is not careful in his observance, we should not be responsible for him possibly performing a transgression. See Halachah 13 where this concept is also mentioned.
If [the purchaser] gave the seller a sela of money from the second tithe, but did not draw the produce into his possession until they were worth two [selaim], what he redeemed is redeemed36I.e., the entire amount of produce is considered as produce of the second tithe, because as soon as the money from the second tithe is paid, its holiness is transferred to the produce. and there is a judgment between the two of them.37I.e., were it ordinary produce, the law would be that the seller should keep his word and complete the transaction. Nevertheless, since according to Rabbinic Law, a transaction is not completed with the payment of money, but rather when the purchaser draws the object into his possession, the purchaser does have the option of retracting. If he does so, however, he must be given the adjuration mi shepara (Hilchot Mechirah 7:1). Should the seller choose that option and retract entirely, he must treat the produce in his possession as produce of the second tithe. If he still wants to carry out the sale at one sela, he must give the purchaser back a sela. The purchaser must consider all the produce as the second tithe, but the sela he was given is ordinary money.

הלכה ט
נָתַן לוֹ סְלָעִים שְׁתַּיִם שֶׁל מַעֲשֵׂר וְלֹא הִסְפִּיק לִמְשֹׁךְ הַפֵּרוֹת עַד שֶׁחָזְרוּ לִהְיוֹת בְּסֶלַע מַה שֶּׁפָּדָה פָּדָה. וּמִדַּת הַדִּין בֵּינֵיהֶם שֶׁהַמַּעֲשֵׂר שֵׁנִי פְּדִיָּתוֹ הִיא מְשִׁיכָתוֹ:
כסף משנה
9.
If [the purchaser] gave the seller two selaim of money from the second tithe, but did not draw the produce into his possession until its worth decreased to a sela, what he redeemed is redeemed,38I.e., the entire amount of produce is considered as produce of the second tithe, because as soon as the money from the second tithe is paid, its holiness is transferred to the produce. and the attribute of judgment must be exercised between them.39I.e., the holiness of the second tithe is transferred to the produce. Nevertheless, from the financial point of view, the purchaser has the option of accepting the adjuration mi shepara and retracting from the transaction. If he takes that option, the seller must return the two selaim to him and from that time on, he may treat them as ordinary money. And the seller must treat the produce as produce of the second tithe. [The rationale for these laws is that] the redemption40The exchange of money for produce or vice versa. of the second tithe is like drawing it into possession.41I.e., just as a business transaction is completed when the purchaser draws it into his possession, the transfer of the holiness of the second tithe is completed upon the payment of money.

הלכה י
מִי שֶׁהָיוּ לוֹ פֵּרוֹת חֻלִּין בִּירוּשָׁלַיִם וְהָיוּ לוֹ מְעוֹת מַעֲשֵׂר שֵׁנִי חוּץ לִירוּשָׁלַיִם אוֹמֵר הֲרֵי הַמָּעוֹת הָהֵם מְחֻלָּלִין עַל הַפֵּרוֹת הָאֵלּוּ וְיֹאכְלֵם שָׁם בְּטָהֳרָה וְיֵצְאוּ אוֹתָן הַמָּעוֹת לְחֻלִּין בִּמְקוֹמָן:
כסף משנה
10.
If a person possessed ordinary produce in Jerusalem and money from the second tithe outside of Jerusalem, he may say: "The holiness of that money is transferred to this produce," and partake of them there in a state of ritual purity. The money then becomes ordinary funds in its location.42As the Rambam states at the conclusion of the following halachah, the money and the produce do not have to be in the same place when the holiness of one is transferred to the other.

הלכה יא
הָיוּ לוֹ מְעוֹת מַעֲשֵׂר שֵׁנִי בִּירוּשָׁלַיִם וְיֵשׁ לוֹ פֵּרוֹת חוּץ לִירוּשָׁלַיִם אוֹמֵר הֲרֵי הַמָּעוֹת הָאֵלּוּ מְחֻלָּלִין עַל פֵּרוֹת הָהֵם וְיֵצְאוּ הַמָּעוֹת לְחֻלִּין וְיַעֲלוּ הַפֵּרוֹת וְיֵאָכְלוּ בִּירוּשָׁלַיִם. שֶׁאֵינוֹ צָרִיךְ לִהְיוֹת הַמָּעוֹת וְהַפֵּרוֹת בְּמָקוֹם אֶחָד בִּשְׁעַת הַחִלּוּל:
כסף משנה
11.
If one had money from the second tithe in Jerusalem and produce outside of Jerusalem, he may say: "The holiness of this money is transferred to that produce." The money then becomes ordinary money and the produce must be brought to Jerusalem and eaten there.43In his Commentary to the Mishnah (Ma'aser Sheni 2:4), the Rambam mentions another general principle that can be derived from this law: the holiness of money in the second tithe can be transferred even when the money is in Jerusalem. As mentioned above, the holiness of produce from the second tithe may not be transferred when that produce is in Jerusalem. For it is not necessary that the money and the produce be in the same place when the holiness of one is transferred to the other.

הלכה יב
מִי שֶׁהָיוּ לוֹ מְעוֹת מַעֲשֵׂר בִּירוּשָׁלַיִם וְצָרִיךְ לָהֶם. וְיֵשׁ לַחֲבֵרוֹ פֵּרוֹת חֻלִּין שֶׁרוֹצֶה לְאָכְלָן. אוֹמֵר לַחֲבֵרוֹ הֲרֵי הַמָּעוֹת הָאֵלּוּ מְחֻלָּלִין עַל פֵּרוֹתֶיךָ וְנִמְצְאוּ אוֹתָם הַפֵּרוֹת לְקוּחוֹת בְּכֶסֶף מַעֲשֵׂר וְיֹאכַל אוֹתָם חֲבֵרוֹ בְּטָהֳרָה. וְלֹא הִפְסִיד כְּלוּם. וְיָצְאוּ הַמָּעוֹת לְחֻלִּין:
כסף משנה
12.
When a person possesses money from the second tithe in Jerusalem which he needs [for other purposes]44I.e., for purposes other than food, drink, or smearing. and a colleague possesses ordinary produce that he desires to eat, he should tell his colleague: "The holiness of this money is transferred to your produce." Thus that produce is considered as purchased with the money of the second tithe. The colleague should then partake of them in a state of ritual purity. Thus he does not lose anything and [his] money becomes as ordinary funds.45Which he may use at will, in Jerusalem or outside that holy city.

הלכה יג
בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁהָיָה חֲבֵרוֹ בַּעַל הַפֵּרוֹת חָבֵר. שֶׁאֵין מוֹסְרִין פֵּרוֹת שֶׁל מַעֲשֵׂר שֵׁנִי שֶׁל וַדַּאי אֶלָּא לְחָבֵר. לְפִיכָךְ אִם הָיוּ הַמָּעוֹת שֶׁל דְּמַאי אוֹמֵר כֵּן אַף לְעַם הָאָרֶץ. וּמֻתָּר לְחַלֵּל מַעֲשֵׂר שֵׁנִי עַל פֵּרוֹת עַם הָאָרֶץ וְעַל מְעוֹתָיו וְאֵין חוֹשְׁשִׁין לָהֶם שֶׁמָּא שֶׁל מַעֲשֵׂר שֵׁנִי הֵם:
כסף משנה
13.
When does the above apply? When his friend who owns the produce is a chavair.46A person who is precise in the observance of the laws of the agricultural laws and the laws of ritual purity. See Hilchot Ma'aser, ch. 10. For produce that is definitely of the second tithe may be given only to a chavair.47For this produce must be eaten in a state of ritual purity and a common person is not precise in his observance of those laws. See Chapter 3, Halachot 8-9. Therefore if the produce was [the second tithe of] demai, he may make such a stipulation with a common person as well.48As mentioned in the notes to Halachah 8, since the obligation above is only Rabbinic in origin, we allow it to be given to a common person even if he might be lax in its observance.
It is permitted to transfer the holiness of produce from the second tithe to produce or money belonging to a common person. We are not concerned that perhaps they are from the second tithe.49Since the common person is not careful in his observance of the second tithe, one might think that he already separated it from his produce, but is considering it as ordinary produce regardless. Were that the case, one could not transfer the holiness of other produce from the second tithe to it [the Rambam's Commentary to the Mishnah (T'vul Yom 4:5)].
The Ra'avad cites the Tosefta (Ma'aser Sheni 4:9) which places certain limitations on making such a transfer. The Radbaz explains that it is possible that these limitations were not accepted as halachah.

הלכה יד
הַמַּנִּיחַ דִּינָר שֶׁל מַעֲשֵׂר לִהְיוֹת אוֹכֵל כְּנֶגְדּוֹ וְהוֹלֵךְ כֵּיוָן שֶׁאָכַל עָלָיו עַד שֶׁלֹּא נִשְׁאַר מִמֶּנּוּ (אֶלָּא) פָּחוֹת מִפְּרוּטָה יָצָא לְחֻלִּין. בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁל דְּמַאי אֲבָל בְּשֶׁל וַדַּאי לֹא יֵצֵא לְחֻלִּין עַד שֶׁיִּשָּׁאֵר מִמֶּנּוּ פָּחוֹת מִשְּׁוֵה פְּרוּטָה אַחַר שֶׁמּוֹסִיפִין אֶת הַחֹמֶשׁ. כְּגוֹן שֶׁנִּשְׁאַר מִמֶּנּוּ פָּחוֹת מֵאַרְבָּעָה חֻמְשֵׁי שְׁוֵה פְּרוּטָה:
כסף משנה
14.
[The following laws apply when a person] sets aside a dinar from the second tithe to [which to transfer the holiness of food that] he eats continuously. If he proceeded to do so to the extent that less than a p'rutah's worth [of its value] remained [consecrated],50I.e., he continued using that coin to redeem produce from the second tithe until all but less than a p'rutah's worth of the coins value had been used to redeem produce. the coin is considered as ordinary money.51And may be used for purposes other than the purchase of food and drink. The rationale is that anything less than a p'rutah's worth of value is not financially significant [the Rambam's Commentary to the Mishnah (Ma'aser Sheni 4:8)].
When does the above apply? With regard to [the second tithe of] demai.52Since the obligation is only of Rabbinic origin, we are more lenient. With regard to produce that is definitely of the second tithe, [the coin] is not considered as ordinary money until less than a p'rutah's worth [of its value] remained [consecrated] after a fifth was added to it, e.g., less than four fifths of a p'rutah's worth [of its value] remain.53In that way, when the fifth (one fifth of the new total) is added, the worth of the entire amount will be less than a p'rutah (ibid.).

הלכה טו
טְמֵאִין וּטְהוֹרִין שֶׁהָיוּ אוֹכְלִין אוֹ שׁוֹתִין כְּאֶחָד בִּירוּשָׁלַיִם. וְרָצוּ הַטְּהוֹרִין לִהְיוֹת אוֹכְלִין מַעֲשֵׂר שֵׁנִי שֶׁלָּהֶם. מַנִּיחִין סֶלַע שֶׁל מַעֲשֵׂר שֵׁנִי וְאוֹמֵר. כָּל שֶׁהַטְּהוֹרִים אוֹכְלִים וְשׁוֹתִין סֶלַע זוֹ מְחֻלָּל עָלָיו. וְתֵצֵא הַסֶּלַע לְחֻלִּין שֶׁהֲרֵי אָכְלוּ וְשָׁתוּ בְּשָׁוְיָהּ בְּטָהֳרָה. וּבִלְבַד שֶׁלֹּא יִגְּעוּ הַטְּמֵאִים בַּמַאֲכָל שֶׁלֹּא יְטַמְּאוּהוּ:
כסף משנה
15.
[The following laws apply when people who are] ritually impure and others who are ritually pure were eating together in Jerusalem and those who were ritually pure desired to [use their money from] the second tithe for food. They should place a sela from the second tithe aside and say: "The holiness of this sela is transferred to everything which those who are ritually pure eat."54The Ra'avad [based on the Jerusalem Talmud (Ma'aser Sheni 2:10)] states that we are speaking about a situation where the person says: "When the person eats or drinks, what he eats or drinks will be retroactively considered as the second tithe from the present time." It is necessary to make this qualification, because otherwise, at the time he eats or drinks, he will be partaking of ordinary food and the consecration would not take effect until the object no longer exists.
The Ra'avad also states that this ruling depends on the principle of bereirah, that retroactively the status of an object can be changed. The Radbaz and the Kessef Mishneh note that there is somewhat of a difficulty in ascribing such a position to the Rambam, for the Rambam maintains that in questions of Scriptural Law, the principle of bereirah does not apply. The Radbaz explains that since there is no prohibition involved, merely the question of when the transfer of holiness takes effect, all authorities agree that the principle of bereirah applies.
The sela is then considered as ordinary property, for they eat and drank its value in a state of ritual purity. [This applies] provided the people who are impure do not touch the food55In certain instances, they may, however, touch the container in which the food is stored. See Ma'aser Sheni 2:10 and the Rambam's commentary for more details.
The commentaries suggest that the restrictions mentioned in Hilchot Ma'achalot Assurot 9:21 should also be observed.
and thus cause it to contract impurity.

זרעים הלכות מעשר שני ונטע רבעי פרק ח
Zeraim Maaser Sheini and Neta Revai Chapter 8