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.
Krylon Fusion paint, sold at most home improvement stores. Designed to bond with plastics, which can have problems with some paints.