If your blow mold no longer lights up, replace the lightbulb, and if that doesn’t work, replace the socket. Consider switching to LED lighting that won’t overheat and will last longer. Repair cracks in a blow mold from the inside using clear epoxy glue and a clear plastic patch cut out from a milk jug or similar piece of plastic. Faded paint on a blow mold can be spruced up with spray paint.