DuoTherm Brisk Aire Yellowed

The a/c cover plenum had become yellowed with age, and the sticker was peeling off. I removed the sticker, washed the plastic then slathered it with Salon Care 40 wrapped it in clear plastic and left it out in the sun all day. This turned the plastic back to its original color. I installed a replacement sticker from Sirum and replaced all the old foam on the inside of the plenum.