I am a veteran soaker. I generally find about an 80% success rate. There are glues that refuse to break down. My biggest success is an album I bought with about 85 Sporting News M101-2 supplements. Almost every HOF in the set. About 60 were glued on paper album pages one on each side. The others were glued to one side of heavy cardboard. Took me a long time to get my nerve up. Finally started on a page that had George Mullin on one side and another non HOFer on the other. Finally got those apart in good shape and started working through them all. They didn't come off easy, maybe 20 minutes to an hour and it took forever to dry and press them. Took me a month, but it was a great success. Finally got down to one that had Matty on one side and Joss on the other. Also had a Cobb/Wagner and a Wagner that tested my cohones. The backs came out pretty clean with 9 slight glue stains on each. The ones glued to cardboard had a different glue and wouldn't budge. Fortunately they were mostly lesser players. Here is the Matty:
