I think maybe it’s a skill you have to practice with. I tried soaking a couple of commons (a 1933 Goudey and a 1952 Bowman) to try and remove some gunk and brighten their appearance. They both definitely looked worse after I soaked them (I think I was too aggressive on the gunk removal process).
I know there are people on here that swear by that process, but I think I’ll just leave it to the experts
