The question is, of course, what you mean by 'restore' precisely, and what sort of damage.

If the damage is scratching or severe warping, or overheat damage (a sort of partial melting of the vinyl which can and could happen), then that may simply be irreparable and render the record unusable. The same for cracking or breakage.

But if it's a matter of the dirt that accumulates with time... they may be unusable, but the thing to try is a big basin (plastic, preferably, to obviate scratching) full of warm water and a bit of dishwashing detergent (the mild sort) or even pure hand soap like Ivory(tm) soap... enough to make a little bit of suds or lather on stirring... take one record at a time, handling by the edges, and immerse it in this soapy warm water, then holding by the edges, sort of swirl it around or lift it up and down while immersed, so that water sloshes forcibly over the surface five times or ten.
Then take the record out, rinse it off (both sides, handling by the edges of course) with medium-temperature water i.e. not hot water, not cold water... then put it on a very clean towel, or doubled fresh paper toweling after a brief drip-dry holding it edge-upward... and let dry without rubbing (which might scratch or damage the surface.)

And so forth, for each record... if a lot of dirt comes off of any record in the lot (or if the wash water becomes even faintly discolored) then dump out that wash water and make a fresh basin-full of warm-water-and-mild-soap before washing any others (to prevent dirt transfering from one record to another.)


If this helps with the problem and answers your question, then please click once on Accept for my Answer. (Only then will I be paid, by deduction of my share from the funds already deposited by you with JustAnswer. Thanks.)
- Favorable feedback is appreciated.