The Sonicare lives on its charging stand located on the edge of her bathroom sink. So I'm thinking the damage is the result of several years' exposure to over-spray from hairspray and other assorted lady-grooming chemicals.
Youtube videos show how to replace the battery and do other mechanical repairs- but I couldn't find anything about replacing the rubber grip panels.
I guess I could just peel them off- but I don;t think she'd be happy with a redneck fix. Any ideas for doing a proper repair?