If an old album of photos has been damaged, whether stuck together or by spilling some sticky liquid, don’t panic. All you need is lukewarm water to save the day.
WikihHow explains how this fix works:
Soak any that are stuck together. Water will not harm most photographs, as exposure to water is actually part of the chemical development process for conventional photographs. If photographs have stuck together: soak the photographs for at least an hour in lukewarm water. Gently peel apart.
Once you peel them apart, it’s best to hang them on a line to dry, being careful to put a single clip on one corner. The same method also works if the photos are drenched with a sticky liquid, although some substances like coffee, tea grape juice and wine don’t come off easily.
How to Save a Wet Photo Album [WikiHow]