This^^ local stores like a lowes, Home Depot, auto parts store, etc will carry a plastic specific paint.Your local auto parts store should sell a plastic trim paint, that should work good.
Heat them with a heat gun. Hair dryer will work but take way longer. If you are just wanting them to look new.
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.Krylon Fusion paint, sold at most home improvement stores. Designed to bond with plastics, which can have problems with some paints.