How about giving it several coats of epoxy-type paint? There are several varieties of paint similar to DuPont Imron that come as a base paint plus a catalyst, and they cure overnight to a coating that's virtually indestructible. Get a paint supplier to mix a small quantity of a color that matches the shade of the insulator pretty closely so it won't stand out once it's coated.
Jerry
Last edited by Hotrod Lincoln; 09/02/2008 1:14 AM.