I appreciate the input of the question of beeswax solvent and will put that information to use next season, as in the meantime I broke down and bought new plastic. The perfect solution, except for cost! I'm particularly intrigued about the 409 and the tri-sodium phosphate, both of which I have on hand. My problems with glass have mostly revolved around breakage while attempting to remove panels that have been propolized in the cabinet slots. The plastic has been far-less vulnerable, but the eventual visibility problem is of concern. Thanks again, Kate ([log in to unmask]) ************************************************************* Kate, I don't know if this would work, but I'll throw it out for consideration: line the inside of the "windows" with clear cellophane; when they get dirty, peel off and replace. my .02 worth, Chris Windsor