I used to collect stamps in my childhood. (I used to collect matchbox covers too, that is a story for another time.) That stamp book got lost sometime after my high school years. On a whim, I recently decided to at least collect the stamps I get in my (dwindling amounts of) snail mail. Most of the US stamps are self-adhesive now and soaking in water wasn't helping. 🖃
This Youtube video showed what products to use to separate self-adhesive stamps: https://www.youtube.com/watch?v=o3TwMX8Be7c