I don't recommend this to anyone but for cleaning, I use this
https://www.oakley.com/en-us/product/WA4230001NC It has removed spots and the microfiber that comes with it hasn't scratched my cluster. My only cluster scratches are from personally being a dumb ass... I wasn't aware of how delicate this surface is so the very first time I used a Starbucks napkin.... big mistake. Lucky though, the marks aren't visible unless its in direct sunlight and maybe a placebo, the solution I used makes them appear less severe.