Cards are getting harder to find. Most casinos use 6 deck packs (pre-shuffled or in order depending on jurisdiction. The ones that can be found sometimes at Dollar Tree are what I call prison cards… Casinos send their used 6 deck packs to the Southern Nevada Correctional Center, the cards are sorted, canceled, repackaged by inmates and are sold wholesale to retailers and sometimes back to the casino.

Where i work… we shred the blackjack and baccarat cards. We cancel and give away our single deck cards used on carnival games.

As filling in holes, too much work. You can wipe off the ink on a card with acetone and reprint a marked card(s) and try to introduce it in a deck… still too much work. A good work friend of mine - retired director of Surveillance told me about that method. His office was right across the hall from me, we talked all the time.