How do you remove an item from the popup list of "Addins Available"?

I have the ability to add items by:
sLibPath = Application.LibraryPath & Application.PathSeparator &
sAddInFullName
'Copy add-in file to the Liblary folder
FileCopy Source:=sAdiPath, Destination:=sLibPath

but removing file from the same library folder doesn't seem to remove it
from the list....