I did a search on the internet and I came across this.
Get some non-acetone nail polish remover that has no fragrance or color added. Next, take a white cloth or paper towel and dip in the remover. Now test on a hidden part of the carpet (corner of a closet or a remnant) by blotting on the carpet. If color transfers to the cloth or the fabric 'melts', contact a carpet care professional. If your carpet is color safe, apply the remover to a white cloth and blot (do not rub) the stained area. This may take some time. Just keep blotting until the stain is gone. If the stain remains, make a solution of 1 teaspoon of dish washing liquild and 1 quart of warm water. Apply with enough of the solution to cover the stain and let soak for 5 minutes. Blot the excess moisture and rinse with warm water. Blot thoroughly with a clean cloth. If the stain reappears after drying, repeat. Aimee Keely from Kansas writes; "This is truly a miracle! I have teal green carpets, and I spilled a deep, dark purple fingernail polish onto it! I used Cutex fingernail polish remover, and dabbed it until the polish was a dull-looking purple. Then I used "10 Seconds Shoe Cleaner" to get up the rest of the nail polish, and you wouldn't believe it! The nail polish isn't there anymore! I'm back to my pretty teal green carpet! Try it...you wont believe it!" Thanks so much Aimee! Janelle writes; "I spilled a dark red nail polish all over the carpet in my apartment. I tried so many different strategies and nothing was working. Until I read this tip and now it's all gone! You mix 1 Tbsp. of ammonia with 1/4 cup of hydrogen peroxide. Saturate the stain with the solution, then place plastic wrap over it. Cover the plastic wrap with heavy books and leave overnight. In the morning, voila! Rinse with water." Thanks a bunch Janelle! I will test this the next time I spill any nail polish and let you all know how it works for me.