Use axcetone when you want nail to be polished off
Put some warm water in a bowl and add a small measure of nail varnish remover; this should soften the polish enough to wipe or scrape it off.
I wouldn't recommend it if you have any cuts, scratches or sensitive skin as it may be a bit sore.
If in doubt, though, I would go the your local nail shop
With nail polish remover.