I wanted to buy expensive crest whitening tooth paste(35e with shipping) as getting good shit off the shelf is impossible in EU, but then I remembered I had some whitening sets left over with solid peroxide content(40%) so I just mix a bit on my tooth brush with normal tooth paste and get like 10x better stuff for free. Seems like much better way to do it in general as strongest paste I found had only 4% peroxide and is expensive af.