What is a good nail polish remover that can be used on the lips without poisons?

I'm sure there must be a good story behind this question...

Fingernail polish dissolves well in acetone. Acetone is not particularly toxic but it should not be taken internally. It is going to burn if your lips are cracked or chapped but not a whole lot worse than the polish itself did when it was initially applied.

The lips do not offer a good substrate for the fingernail polish to adhere to so the best fingernail polish remover would be "time".