Diecast cars are mostly a metal mix, which is commonly known as "white metal". It's tin, zinc, antimony, etc., and there's simple alternative to manually sanding paint. You can easily strip it with acetone bath! I personally use cheap but strong nail polish remover (ammonia based). Pop car inside the glass jar, wait 1-2 days, and wipe both chemicals and paint with paper cloth. This bath results in clean, exposed metal, which quickly (10-30 minutes) oxidizes so after wiping it, I'd advise to apply thin coat of primer or clear varnish to prevent situation where paint would be applied to grainy or loose particles. This will prevent paint from peeling in the future. Never apply ammonia to plastics as it will melt them After that, it's just adding bits, painting - the usual ;)
These look great. It's so much fun to make Gaslands cars: I've had a hoot making them with my 10 YO so. He does want to make 50 point cars with everything but the kitchen sink though!
