Here are some simple ways to reuse old nail polish: Vibrant hues can be used to paint different keys different colors; think deep for the front door, purple for the mailbox, etc. Torn window screens can be mended using clear nail polish -- just apply it and let it dry. You won't be able to see where you've applied the polish! Trying to thread a needle can be challenging. Make it easier by dipping the thread end in nail polish to make it stiff and easy to fit through the needle's eye.