I own a ridiculous amount of nail polish. The picture is probably about 5% of all the different polishes I have in my collection. I love painting my nails--I do it almost daily--but there are also bunches of other ways to use nail polish that doesn't involve giving yourself a fab mani or pedi.
Prevent Jewelry from Tarnishing
I love fun costume jewelry, but seeing that hint of green that winds up on my fingers isn't pretty. Prevent this faux pas by painting a clear coat on the inside of that goegey ring you just bought, and you'll be good to go.
Color Code Objects
Use different colored polishes to paint objects that look similar so you can tell them apart. Paint different shades on your set of keys so your roommate stops grabbing yours by mistake!
Paint the Sole of Your High-Heels (think Christian Louboutin):
One of my friends did this, and it's actually a fabulous idea. It's a super easy (and cheap!) way to model your shoes after the highly coveted brand, and give them a fresh new look. You don't have to go with the classic red, either. Revealing a glitzy purple hue on your soles looks just as great.
Stop Runs in their Tracks
This is a classic use for clear nail polish, and it works better than anything else. You can stop runs in stockings by dabbing polish at both ends. This way you can get more wear out of your fave tights, even after a tiny tear.
Cover Up Your Scuffs
Cover up a scratch on scuffed shoes or boots by applying a coat of black or brown (or whatever color your shoes are) nail polish to your shoes. Make sure to apply a top coat so that the polish lasts.
There are tons of other ways to use your polish, but these are the things I tend to do most often. It's also a great excuse to go out and buy another pink polish when your boyfriend simply doesn't understand that owning 20 different pink hues is totally necessary.