Removing strap changing marks

[Tinker]

I use Bergeon 2290 polishing sticks, 3 grades on one stick and literally only a few quid to buy.

Yep, they're very good.

If you're prepared to spend time in the nail section of the big chemists' - Superdrug, Boot's and so on - you can find very similar (and a bit cheaper) or you can buy the Bergeon from Amazon for seven-plus quid.