Halloween // Blow Mold Help!!

I absolutely adore my Halloween blow mold decorations, but they have started to become very sun-bleached and faded. I was wondering if there’s anything I can do to restore my Halloween blow mold decorations?? I don’t want to spray paint them because then light won’t shine through. But is there a stain or something else that you all use to re-stain your blow molds? I will continue to set my decorations out no matter what, but I would love to touch them up and make them look new again. Thanks for your help!!