Go over them again with acetone nail polish remover and a cotton ball. 100% acetone works better than anything else I've used. Use an orange stick dipped in the nail polish remover to get the edges of the nails where the nail meets the skin.

After getting them fully clean, soak them in warm water with a few drops of dish soap, and peroxide so that the water is half peroxide. Scrub gently with a nail brush, and go over the edges again with orange stick ...you know the ones that are flat on one side..remove any deadened skin and around where the nail meets the skin, and push back the cuticle.

It can take a couple of applications of the nail polish remover to get it all. Anymore, I don't bother with standard nail polish remover. I go for the good stuff. It does a better job and you don't have to use as much.

I do my natural nails frequently as I like to do manicures. The technique above works well at even getting dark reds off, so yellow should be pretty easy.