wALKED INTO A SHOP THE OTHER DAY TO BUY A MOVIE, AND ASKED IF HE HAD A CLEANER, ,I have  several discs that are the worse for wear, hIS RESPONCE WAS , cERTAINLY sIR, WHAT SORT, WHEREAPON HE SHOWED ME SEVERAL AND EXPLAINED THE PROCESS TO ME
Are you aware that the disc can be sanded down,  by doing this the laser is true and in the groove so to speak  ,if not it is deflected and it stuffs the pic,and he told me that you sand the shiny part down and if the label is damaged it has ruined the reflective side and the laser goes right throught so that it is blank
and there is a disc with little brushes glued on it which plays a lot of groovey music and when it gets to track 15 it cleans the lens on the machine
Ahhhhhh where would we be without technology but a very helpful fella, and quite an education

the disc with the little brushes on it only cleans the laser head on your cd/dvd player, 

there are various "cleaners" on the market (one look at ebay will confim this) but if your disc is scratched, and that is sooooo easy to do then you must go the next step
 
which is "polishing" the thing this involves various stages of very minute cutting and polishing, much like a gemstone,
 
the best machine on the market available to the general public at a reasonable cost currently retails on ebay for about $199  

this involves sanding discs and polishing fluids of various substances

some of the cheaper ones work sometimes but it is a bit hit and miss as to which ones do or dont

So I cheat. Whenever I get as DVD or CD I burn a copy of it strictly for archival purposes, put the good one away and use the copy, when it becomes unplayable do what the younger generation do with everything, throw it away and burn another copy from my master.....
I have not had a lot of luck de scratching cd's.....