Here a quick solution to those who suffer from stained nails, either from a specific nail polish colour, or the yellowing of the nails. You can easily take care of that yourself with some household products:
1 tablespoon of baking powder
a little olive oil
a few squeezes of lemon juice
an old toothbrush
Mix it in a bowl and rub it on your nails with an old toothbrush. Rinse with warm water after 5 minutes, and you're done! I would not recommend doing this too often, but every once in a while it couldn't hurt!
Take care of your nails by applying some caring nail balm or butter, to hydrate them. Use the cuticle remover to push back the cuticles and improve nail growth.