Selectively removing footnote number with footcite in beamer

My question is identical to this one, which asks how to remove footnote numbers from the footcite command within Beamer. The accepted answer, which is the command

makeatletter
def@makefnmark{}
makeatletter

removes the numbering completely. I would like to be able to remove the numbering selectively, and show the numbers on some slides while hiding it on others. How can I accomplish this?