I bought this 2018 Allen & Ginter Shohei Ohtani rookie last year for a discount because it had a couple dents along its edges. A year later, I finally got around to fixing it. Basically, you put the card in a humidor for a few hours at 80% humidity, let it dry for 8 hours under gentle pressure, then repeat the process a few times until the dent goes away. You can use a bone tool to gently smooth things out and work the cardboard, but the goal is to let the cardboard repair itself naturally as it expands and contracts with the introduction/removal of humidity. You can also put a tiny bit 10% isopropyl alcohol/90% distilled water on the dent with a Q-tip, but you have to be super careful to not use too much and immediately dry the card under light pressure.