Yellowing decals

Searched the forum and faq, couldn't find it (its there somewhere, i know).

How do you counter yellowed decals? is there a solvent or something, something that coats your decals?

I heard taping them to the window and leaving them get sun helps to cure that.

Yeah, tape it to the window for a couple of weeks and the sun will
work for you. It did for me anyhow.

okay thanks, i'll try it!