Depends on the depth and type of scratches
Saturn rings or simply rings are easy if superficial, someone skiller with a normal cleaner can do it
Snow/points under the disc is a clear sign you fucked up, might be cleaned if superficial but rarely return
Key scratches are easy too unlike some people might say but you need a skiller guy
Fog and random scratchiness like pic related is mostly superficial, same with a good guy you can get rid of them and even a newbie can clean them if they are few
But when key lines and rings are deep you might need a bad boy like first pic, in some cases only works if the disc was never cleaned before.
It simply gives your disc a good old rub and erases a certain layer(s) depending on the stone disc placed, making it thinner along the way.
Only in extreme cases or if the scratches are superficial but like your pic related
It can clean snow but it's rare because it mostly presented near the label
But none of these will work if the disc is rotting and/or if the layer is cheap and it's degrading in the sides/inner rim
Second pic is a normal decoloration in cheap discs (or if you are a dirty harry), it bloats over time and damages the magic inside, EA and Activision games are infamous in normie forums because they are even bloated when brand new
Third pic is just some nasty fella with a cheap disc or simply a cheap disc left unboxed in very humid atmosphere
End of the line is like anon said: Make digital copies of your stuff because it's even legal (unless from a uncool country), box your discs in dry places with acid-free containers/boxes
If you collect feel better because the box is what really counts when you brag about a collection