I suggested using the non-metal scouring pad (Scotch-Brite) to take off things like sunburn or cigarette burns. It is a light abrasive which removes some of the damaged clay surface of the chip. I rarely have to use such harsh means...................Usually to just clean a dirty/soiled chip, I use a pared down old toothbrush and some mild soap under warm or hot water; then I dry; then I apply sewing machine or mineral oil (not cooking oil) and rub the chip dry of the oil.................Lately in my old age, I am too lazy to do anything; I leave the chip as I found it.

Robt.