I'm intrigued by this. I have the same problem - wear nail polish on my toes because they're yellowed. I'll have to check for this next time I'm shopping!

I always have nail varnish on my toenails, always, and they look pretty stained and yellow without it (which is probably why I always wear the stuff, which then makes it worse, a vicious circle!) This is a really good product, much better than the anti-stain basecoat by Nails Inc that I bought. You buff the nails with the little file, apply a clear gel, which must work at removing the stain from the nail plate, and then when the gel is dry, apply a clear coat of special anti-stain varnish. You don't even need to use a further basecoat. My nails still have a slight tint of pale yellow, but much less than before, and that is only after using this product twice.