there is a company now that makes a spray on titanium dioxide coating.. reccomends you use it on everything that comes in contact with UV light.. like kitchen countertops and stuff.. it comes in an aresol can and I can probably dig up a link if necessary.. Im thinking of spraying it on the mylar.. Their ad says it lasts a year.

Im pretty sure these lights are ozone creating lights (not ion) but I cant remember where I read that..