I used JASCO paint stripper. Got it at Home Depot. Wear rubber gloves, brush it on, wait for paint to blister and scrape it off with a plastic scraper. Doesn't hurt the fenders.
I wouldnt sand blast the plastic... sand blasting can tear through aluminum quite easily.
Use carb/brake cleaner. That should do it. Paint stripper can be used as said before, just dont leave it on the plastic for too long! As soon as the paint bubbles up, scrape it down and wash it thoroughly.
airplane paint remover. spray it on let it wet for a few minutes then spray it with a hose and done. turned my painted black plastics to pure white. any of your local auto parts stores (advanced auto, pep boys, auto zone) should have some kind of paint remover if not that one.
carb cleaner all the way!!! check my pics in the how to shine your plastics thread. all we used to clean them was carb cleaner ,scotchbrite pad ,hot soapy water and paper towels. what a mess but the end result was worth it.
I used a combination of acetone and alcohol mixed together let it set for a few seconds then wipe it clean with a rag. you can also use xyline its only like 4 dollars for a pint at home depot