The lustre is often lost, cleaning leaves tiny scratches - all the reasons for not cleaning coins. That said, if you don't care that you are substantially reducing any value, why not? Tokens (especially recent ones) don't seem to retain a lot of value, even with the conversion to TITOs making tokens obsolete. If you wanted to have a fancy display and have no intention of selling or trading them, it might be OK. Even so, if a $1 token has trouble selling for even face value, how much can you possibly lose? But my first instinct - as a coin collector - would be to say "no."