Over the years, I have amassed a large collection of CDs SACDs DVD-As etc. Some of them have seen better days and few are perfect surface wise. Is there a method to resurface some of the worst ones, some of which are irreplaceable?
I've had good success with a product I bought a number of years ago, called "CD Doctor". The box says Orbyx Electronics Nexxtech, Concord, ON, L4K 4M3, Product of Canada. I found some of the words online, may be worth following up. The kit contains paper cleaning cloths and a paste that goes beyond the spray type cleaners I use for less damaged discs and does actually repair some scratches. I don't know if this is the same product: https://www.shopoakville.com/CdDoctor/?
The best way I've found to preserve my CD's is to rip them using Exact Audio Copy. I have a couple of heavily damaged discs that skip badly in a CD transport or CD ROM tray, which ripping was able to restore. It took several hours for the program to rip my copy of Pearl Jam Ten, but it plays perfectly as a file in my NAS. I assume I could burn it onto a blank disc, but I've not bothered because my CD's have been copied to my NAS as zero compression FLAC files.
Highly recommend the Mapleshade "Mikrosmooth" product. After that, I treat each disc using "L'art du Son" and then demagnetize. I've done this with all my new CD's for numerous years. Only down side is that you may see some small "swirls" on the disc surface post Mapleshade. And it should repair your surface CD imperfection problems to a playable condition. To my ears, it really makes a difference for the better.