Popwhite Whitening Primer + Toothpaste Consider this Popwhite Whitening Primer + Toothpaste ($24) a purple shampoo for your mouth. Since purple and yellow are colors that cancel each other out, this peppermint and coconut oil-infused product erases any stains to brighten your teeth. Popwhite Whitening Primer + Toothpaste $24 from dermstore.com Buy Now