I know this is an old thread, but I wanted to add a successful technique to the conversation for any future needs.
Had an accident where water leaked through the floor from the first floor laundry room to my basement workshop. Decals found stuck to instruction sheet after everything was cleaned up and dried.
Used a Joy brand My Little Steamer clothing steamer to successfully separate the decals from the instruction sheet. Steam was gradually and gently applied to the instruction sheet and the decals gently pried off. The decals are still usable and the instructions are still legible and useful. Some adhesive from the decal sheet remained stuck to the instructions so I let the instructions thoroughly dry before attempting to fold and store them for future use. I inserted waxed paper between the pages as a precaution against any potential sticking between the instruction pages.