One of the things that drives me crazy is naked Barbies. I swear the first thing kids do is strip Barbie down to immodesty and then they leave her laying around. We had a rule in our house, if Barbie ended up laying around indecent, the Barbie was taken away and she had to earn her back.
Even with a rule, we still ended up with Barbie laying around in all states of undress. I decided it was time to cover up Barbie once and for all. Our of all the different paints I tried, nail polish worked the best. It often only needed one coat and has lasted throughout hours and hours of play.
Painting clothes on a Barbie is super easy, first pull up their hair to prevent accidentally coloring any strands or ending up with streaky clothes. Use a dark color of nail polish. This ensures that it stands out against the Barbie and will also require fewer coats. The great thing about painting Barbies is they have some natural guide lines and it is pretty hard to go wrong. Paint one coat on the Barbie and allow to dry thoroughly, I usually let them dry over night just to be sure. If the swim suit looks streaky or translucent, paint another coat.
I painted several different types of swim suits, including some one pieces and bikinis. Both have worked great under many different kinds of Barbie clothes and they have put an end to the battle of keeping the Barbies dressed.