Why do some purchase an extra set for pesach? I put my grates in the oven when I self clean. So easily kashered!
They get discolored in the self clean cycle and the coating that allows pots to glide easily from one burner to the next without lifting the pot becomes matte and the finish doesn't allow for gliding anymore.
besides for the finish coming off/chipping/discoloring and the rubber feet melting, I know a few ppl who's grates cracked in the self clean. they are not meant for self cleaning - if you do it's at your own risk, and its not cheap to replace. also the companies usually go out of stock before pesach - so don't wait till right before to self clean them if you don't have a backup option