Gemara

(Beraisa - R. Meir): If one said 'this loaf is Hekdesh', if anyone eats it, they transgress Me'ilah; therefore, it can be redeemed. If he said 'it is Hekdesh to me', only he transgresses Me'ilah if he eats it; therefore, it cannot be redeemed;

Chachamim say, there is no Me'ilah for benefit from Konamos (forbidding something like a Korban), no matter who eats it.

The opinions must be switched. R. Meir says, there is no Me'ilah for benefit from Konamos. Chachamim say, only he transgresses Me'ilah if he eats it.

Nedarim 28b (Rava): Kedushas Damim (monetary Kedushah) can vanish, but Kedushas ha'Guf (intrinsic Kedushah) cannot vanish.

(Abaye): Also intrinsic Kedushah can vanish!

Bar Pada holds that even Kedushas Damim cannot vanish.

Kesuvos 59a - Contradiction: Shmuel rules that if a wife vowed 'what my hands produce is Konam to your mouth', he should annul it, lest he divorce her and be unable to remarry her. He also rules that Hekdesh does not take effect on something not yet in the world!

Answer (Rav Ashi): Konamos are different. They are like Hekdesh ha'Guf, like Rava taught:

(Rava): The following uproot a lien: (the collateral was made) Hekdesh, the Isur of Chametz, and freedom (the collateral was a slave).

Chachamim strengthened the lien of a husband, therefore her earnings do not become Hekdesh now.

70a (Mishnah): If one vowed that his wife may not benefit from him, up to 30 days, he gets someone to finance her.

Question: He is obligated to her! How can he uproot his obligation through a vow?!

Erchin 23b (Mishnah): If Reuven owed a Kesuvah and was Makdish his property, his creditor may not take the property from Hekdesh. Rather, the redeemer redeems the property in order to pay the debt. If the property is worth 90 and the debt is 100, he adds a Dinar and redeems it to pay the debt.

Question: Why does it say "the redeemer redeems"?

Answer: This is due to R. Avahu's reason, lest people say that Hekdesh becomes Chulin without redemption.

Bava Kama 89b (Beraisa #1): If Leah brought a slave into her marriage to be Melug property, if she destroys a limb of his, the slave goes free, but not if her husband destroys a limb.

(Beraisa #2): He does not go free whether he or she destroys a limb.

90a Suggestion: Tana #1 holds like Rava, and Tana #2 disagrees!

Rejection: Even Tana #2 holds like Rava. Chachamim strengthened a husband's lien on his wife's property (so freedom does not uproot his lien).

Rishonim

Rambam (Hilchos Malveh 18:7): If one was Makdish his property, his creditor cannot take it from Hekdesh, for Hekdesh uproots liens. When one redeems the land from Hekdesh, we estimate how much one would like to pay for the field in order to give it to the creditor. Therefore, after Ploni redeems it, it is Chulin in his hands, and the creditor collects it.

Rebuttal (Ra'avad Hilchos Erchin 14:7): Hekdesh did not uproot the lien. The redemption is a token amount, lest people say that Hekdesh becomes Chulin without redemption. Only Kedushas ha'Guf, e.g. Konamos or garments put on a Mes (to be shrouds), uproot liens.

Magid Mishneh: The Rambam holds that all Hekdesh, even Kedushas Damim, uproots liens. Rava taught that all Hekdesh uproots liens. The Mishnah in Erchin says 'lest people say that Hekdesh becomes Chulin without redemption.' I.e. this is why Chachamim said that Kedushas Damim uproots liens, even though the creditor will collect it from the redeemer. Hekdesh profits a little, lest people belittle other Hekdesh and say that it becomes Chulin without redemption. Hekdesh ha'Guf permanently uproots liens. Kedushas Damim uproots a lien until it is redeemed. The Ra'avad and all the Meforshim argue with the Rambam. Really, Kedushas Damim does not uproot liens. The Mishnah in Erchin is not because the Hekdesh uprooted the lien. Rather, we require a Dinar lest people say that Hekdesh becomes Chulin without redemption.

Ran (DH Kesuvos 24a DH v'Ika): Rashi explains 'Konamos are different. They are like Hekdesh ha'Guf' to mean that just like one cannot redeem a Korban, one cannot redeem Konamos to permit them. Therefore, it is like Kedushas ha'Guf to uproot liens. If one put a lien on his ox to his creditor, and he was Makdish the ox for a Korban, the creditor collects from elsewhere and the ox is a Kosher Korban. It is not stolen. Kedushas Damim, i.e. for Bedek ha'Bayis, does not uproot liens, like it says in Erchin, that he adds a Dinar and redeems the property. We discuss when he put a lien on (the ox, or other) Metaltelim Agav (along with) land. If not, even (selling or giving to) a person uproots the lien, and all the more so Kedushas Damim, which is like giving to Hekdesh. Hekdesh is no weaker than a person! If one made an ox an Apotiki (designated it to pay a loan, but not along with land), if he sold it, the lender cannot collect from it. A Gabai'on explained like Rashi. R. Tam says that even Kedushas Damim uproots liens. This is wrong.

Tosfos (59b DH Konamos): If Konam uproots liens, any borrower can stop his creditor from collecting! Rather, Chachamim strengthened a creditor's lien, just like they strengthened a husband's lien. This is not only for a husband. The Gemara (70a) asked how a man can forbid his wife, i.e. for also a wife's lien was strengthened. The lien was strengthened only against a Konam to the creditor, but not if it forbids to everyone, like the case of the shrouds. Rava holds like the Tana who says that Melug slaves go free if she destroys a limb, but not if he does. Alternatively, her husband has more rights than her (more than a mere lien, therefore, they do not go free even if she destroys a limb).

Gra (25): Chachamim strengthened a husband's lien even regarding freedom, which is like Hekdesh.

Nimukei Yosef (Yevamos 22b Sof Dibur Rishon): Some learn from Rava (in Kesuvos) that one can forbid his property (through Konam) to his creditor, but we excommunicate him until he permits his vow. Even if he vowed Al Da'as Rabim (according to the will of (at least three) others), he can permit it for the Mitzvah to pay his debt. The Ri says that (he need not permit it, for) Chachamim strengthened the lien of a creditor, lest the debtor forbid his property to them. They did not do so regarding shrouds, for it is not common, and for the honor of the Mes.

Poskim

Shulchan Aruch (CM 117:7): Isur Hana'ah uproots a lien, just like Kedushas ha'Guf does.

Rema: However, Kedushas Damim does not uproot a lien. Rather, the creditor redeems it for a small amount, lest people say that Hekdesh becomes Chulin without redemption. The redemption money is added to the debt, and he collects it from the borrower. Even Kedushas ha'Guf he cannot forbid to only the lender, e.g. 'my property is Konam to him.' He can forbid it only to the entire world. Some disagree.

SMA (24): The dissenting opinion says that he can forbid just the lender. However, we excommunicate him until he permits his vow.

Bedek ha'Bayis: Hekdesh nowadays is for the poor. All agree that it does not uproot liens.

Ketzos ha'Choshen (2 DH uleha'Rambam): The Ra'avad holds like Tosfos, that once Kedushas ha'Guf takes effect, it stays. He rules (in Hilchos Pesulei ha'Mukdashim) like Bar Pada, that even Kedushas Damim cannot vanish. The Ra'avad hold that Kedushas Damim is light, and it does not uproot liens; the redemption is needed only due to R. Avahu's concern. Since he holds that it does not vanish, once it takes effect, it should not vanish! In Erchin, Bar Pada agrees that one need not redeem for the full value. He said only that some redemption is needed to become Chulin. A fortune of Hekdesh can be redeemed on one Perutah (Kidushin 11b). However, here the Ra'avad said that the redemption is only due to R. Avahu. According to Bar Pada, letter of the law it is required! It seems that since the lender takes (from Hekdesh), for him it is not for nought. His lien is like giving money. The Rashba (Gitin 40b DH ked'Rava) says so. The Rambam holds that even Kedushas Damim uproots liens. Even though he holds that Kedushas Damim can vanish, that is only when he was Makdish only for a limited time. When the time expires, his Hekdesh expires. A borrower was Makdish permanently, just the lender takes it. Since we say that he collects from now and onwards (not retroactively), the Kedushah took effect before he collects, so it does not vanish.

Ketzos ha'Choshen (5 DH Emnam): We hold that a Konam Klali (it forbids everyone) can be redeemed, so it is like Kedushas Damim. It does not uproot a lien, for it can be permitted. We say that Konamos uproot liens (Kesuvos 59b, unless Chachamim strengthened the lien), i.e. when he forbids only one person. It is like Kedushas ha'Guf, which cannot be redeemed.