I can only state the obvious when using any product for cleaning. Don't go too far too fast or you may end up without the card you had to start with. Back when I was trying to take stickers off of cards, I tried varied stuff that was around the house to get the adhesive residue that remained. One of the best things for this was nail polish remover. But to my regret I found that will dissolve off the magnetic strip if you get it on the back of the card. And who wants a card with all or part of the magnetic strip washed off? Cards are often "harvested" in great extremes off the machine tops -- anywhere from perfect shape to horribly worn, bent or multiple raggedly holed. I think the whole point of collecting blanks is to be assured of getting a card without a trace of wear, as it has never been used. All of you know that the more a card is fed into and pulled from the card reader slot, the more the surface will get scratched and worn. The next best card to a blank for most people is a card they or another collector has obtained, as you are generally looking at a card that was issued and quickly placed in the person's pocket. Brand new, imprinted, but not with any wear. The only flaw is the casino desk where you get a card and they punch a hole before or in spite of your request that they shouldn't... ("Oh, I'll punch it so you'll know which end goes in the machine.")

But for cards harvested off the machine tops (where I look upon them as fair game, since they were abandoned by the person named on the card) that need cleaning due to sweat, grime and dirt, try a household cleaner that will disolve the material, but without any kind of granular material (like a scouring powder) which would scratch the surface of the card while you scrub.

Regarding the practice of removing material from a card (like the name imprint) to make a card look like a blank card, that is fraud. The removal of a name is altering the card itself. Even if the card was printed and never used, use of a solvent to take the name off still may affect the surface of the card in some way that may not be noticeable right away. Could some of the solvent permeate the card and warp or cause color changes in the future? I don't know. But just any chance of that means the person who is getting that "blank card" should know the card has been "altered" to achieve "blank" status. Perhaps instead of refering to them as "blank cards" we should call them "never imprinted cards." Of course, that would never happen. The "Blank Card" term is already entered our vocabulary and is in general use. The same way collectors refer to valuble comic books as "Mint" condition, even though the ideal shape is the way they were printed, not minted.