Fred,
As there's not an easy way to repair the pages, I think I'll make my own pages to replace the damaged ones. Do you see any reason why the undamaged pages might still have unseen residue that would warrant replacing the entire album?

Peter,
As it happens I do have a chemistry lab available to me but that seems a bit extreme unless I find something really valuable! The only stamp-related activity I've conducted in the lab is using their nice microscope to look at some flyspecks.
Seeing as the stamps are damaged anyway I think I may as well try soapy water and maybe dilute bleach solution. Too bad for the MNH ones but they're not M anymore anyway.

Thank you both for your suggestions!
Karen