How to make it:
-Fill the bowl with warm water.
-Add a drop of nail polish to the water and let it spread out. You can also use a skewer to swirl the color around a bit to give it the effect you’d like.
-Dip your mug in the water.
-You can use nail polish remover to remove any excess nail polish on the bottom and inside of the mug or sections that got messed up.
-Carefully pat mug dry with paper towel.
-You can repeat with additional colors if you want.
-Once you’ve achieved the look you want, let it sit for at least two hours.
I would recommend hand washing these mugs. (Although I haven’t tried mine in the dishwasher yet!) Durability will also depend on quality of the nail polish a bit – just as it would on your nails. I let mine sit for about 5 hours then scrubbed them and they were fine. If you run into problems, try coating the outside with a clear coat of nail polish or a non toxic finishing spray.
source : http://thediygirl.tumblr.com/