isinglass cleaning
 

I am having problems with the isinglass on my boat. There is
something on the isinglass that will not come off no matter what I
have tried to clean it with. I have tried a couple cleaners on the
market, but, this cleaner is only for normal maintenance. This a some
kind of film. Anyone out there have any suggestions on what I could
try to clean it without destroying the isinglass. Any suggestions
would be appreciated. :?