Personally I'd leave them in.
But they should soak easily.
Just regular water, leave them in a few minutes maybe long enough they just float off.
Doing one page while in the book is challenging, although the part farther away from the fold will be easiest
For drying a stamp drying book would be the best way, if not, laying them face down on a paper towel with no patterns or wax paper works well.
https://subwaystamp.com/products/sho...1-2-size?gQT=1