Hello! I have the white CMF Buds Pro 2’s as well and I could not get the discoloration to come off. Mine, from general Human liquids and holding my case, it built up quick. I had to buy a 3rd party protective shell, to keep from the finish colour continually changing.
Hope this helps, but if you have the white ones, I truly think it is a finish problem on the product, I have tried all different materials to cue tip and microfibre for cleaning