@Badolwen@jake4480@buru5 There are whitening toothpastes, but afaik they work by rubbing down the outer layer of the teeth. It can have detrimental effect on tooth health, and I'm not sure if it'll have a guaranteed effect.
I see nothing wrong with doing something against the yellow color if you don't like it. It's not like you have to go overboard and make it unnaturally white.