Q. I heard once that there is a minhag not to handle money during Tisha Beav. Is that really so?
A. Nitei Gavriel (Bein Hametzarim 2: 79: 17) indeed quotes from Machzor Meaglei Tzedek, that there is an ancient minhag for some, not to handle money before chatzos on Tisha Beav. (Presumably for concentrating and not forgetting the mourning of the day). However, that does not include the monies given for tzedaka, as he mentions there.
As usual Horav Shlomo Miller’s Shlit’a opinion is that one should keep the minhogim of his family and community.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a