S.O.
The trays and the bleach from the dentist is the only thing that worked on me. (I had grey stains on some teeth from antibiotics I got as a baby when I was very ill.)
I paid $125 for the trays to be made and 6 tubes of the gel. Sounds like a lot until I total up all the Over the Counter things I tried that didn't work and realize I probably paid more for all the other stuff.....