my nephew spray painted his garage with a sprayer, didn't realize he had gaps where he was spraying and he sprayed his motorcycle on the inside
he used a pressure washer....on every surface including the leather bags

it took it right off the clear coat, no plastic that I know of, but it carved into the leather on the bags, it was a mistake to try on leather
i'd start with a green scrubby pad and some apc
he had little flecks left on the clear coat, btw, and I as able to get them with a clay bar and lube
good luck, sir
and be careful with oil based solvents (thinner, spirits, etc) and oil based materials (plastic)....test spot

......not meaning to step on toes, but I'm shaking my head a bit and suggesting caution, once you chemically dissolve or change the surface, there is no going back