Actually have not had to worry about one as I haven't had one to worry about
I did talk to Craig at Griswold Aviation, Skymaster Top Service, and he has had them stick on other airplanes but not on any Skymaster's. He said that he has read in service manuals before about cleaning these units. I haven't looked in the P model SM because it is at home and I am down in Florida but I can look when I return Thursday