What is the code you are getting, and which engine?
It is extremely rare for these cats to clog or break up, unless there is another underlying engine problem, a serious one at that. These cats are constructed out of a wire mesh, so are unable to "break up", or melt, unlike many other vehicles. If clogged or damaged, they will not "unclog" themselves either.
It is more common for the catalysts in these to deteriorate, reducing their ability to store oxygen. That should give you a P0420 or 0421 code.