Nail polish remover is acetone which can soften or remove paint. It also has skin and nail conditioners in it that could cause issues with the new paint.
Alchoal(Higher the % the better) GooGone,Wd40,Gas,Ligher Fluid,Brake fluid,Warm Wet Towel with water or Pine Sol, Toilet Bowl Cleaner, Windex, If its a full on decal and not residue steam like from a boiling kettle it'll lift it up.