get a polishing cloth, or a cotton t-shirt and pour a bit of VERONUNG or VERUNUNG on, and wipe away at the model as you would to polish it, the name i have given you soundz completly fukt up, but thats its german name, i don't hav the english name sorry i recieved a soft drink bottle full of it from a friend who got it from a factory, so i'm not sure if this product is available to buy.
when wiped on a painted surface, it will completely remove laquer, primer, enamels away and lead you back to a shiny plastic molding colour, does not melt plastic
I tryed this on one of my old crapper models, which had way too much paint sprayed on one side, and this chemical completly disolved the paint and it just ended up on the rag
in a nutshell this stuff is like polishing compound except ULTRA times more pwerful