I'm really new at this but here's the regimen that I've used thus far and results have been good.
I put the pads in a bucket of soapy water & let 'em soak for a while, then squeeze the pads a few times underwater, rub the surface of the pad by hand underwater, lift the pad out of the bucket & squeeze it dry, and then repeat in a fresh bucket of soapy water.
Do the soapy bucket thing at least 2x, perhaps 3x, and then do a 4th time in a bucket of clean water, no soap. The sealant (EX-P, UPP, FMJ) pad will probably be the toughest to clean thoroughly.
Mount 'em on your buffer & spin em if you want ..... you'll get wet.
I squeeze the pad dry as much as I can then put it individually on a towel face down, lay a towel over it and press down ... repeat until mostly dry & then let air dry.
Do the next pad on a dry part of the, towel etc ............
When dry, I put the pad back in the plastic bag it can in. I mark the bag with the product that I used to eliminate the possibility of cross-contamination.