Q. Is it correct to write on the collection plate machatzis hashekel, or we should rather write “zecher” lemachatzis, so it would not become actually kadosh?

A.We find in Maseches Sofrim (21:3) that one shouldn’t say he is giving the machatzis hashekel for atonement but only as a voluntary act. Darchei Moshe 694:1 quotes the above from the Chidushei Aguda. Following this, Chazon Ovadyah (Purim p. 101) writes that one shouldn’t call it machatzis hashhekel but rather “zecher” lemachatzis hashekel, so that people won’t think, one is actually making it hekdesh. Toras Hamoadim (p. 96), Zichronos Eliyahu (Shin; 2), and Shalmei Todah (Purim pg 270) agree. This is in opposition to Divrei Yosef (52) who says that it may become forbidden in benefit and even saying that it is Zecher Lemachatzis HaShekel is an issue. However, Zecher Simcha (76) and Kovetz Divrei Zeev (20: p. 10) rule that it is permitted to call it machatzis hashekel. Nitei Gavriel (Purim 8: 2) maintains that on the onset (lechatchila) it should be addressed as zecher lemachatzis hashekel. See also Shulchan Aruch (O.H. 469: 1) that prohibits saying; “this meat is for Pesach,” as it may be seen as consecrating a korban. However Mishna Berura (ibid.) maintains that it is permitted after the fact.
Horav Shlomo Miller’s Shlit’a opinion is that there is no issue in calling the donation machatzis hashekel, as the vast majority of people do, since everyone knows that the donation purpose is for tzedaka and not to consecrate the coin for kodshim use. He pointed out to the Mishna (Nedarim 18b) that maintains people donate to items that they are familiar with. He added that today, since it is so common to write on anything including meats “Kosher Lepesach” (and not “Kosher al Pesach” as required by Shulchan Aruch (ibid.), there is no more point to avoid saying this meat is for Pesach and is similar to writing just machatzis hashekel.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a