Anyone tried these for foxing?

This is a good question for a conservator, but this forum is really meant for amateurs and I would never recommend applying any chemical to foxing on a page bound in a book. When conservators use chemicals to ameliorate foxing, they dis-bind the book and work on individual pages so that the chemicals can be washed out of the pages. Anything you apply directly will stay in the paper fibers and continue to act on them long after you wish they would stop. For instance, I know people who have applied hydrogen peroxide to the foxing spots and while it may make it look better temporarily, it will continue to destroy the fibers with the acid of the solution. This is only a way to ruin your book.

Thank you so much for your quick answer! I do painting conservation but am new to books so wasn't sure if the idea would transfer over or not. Sounds like it's not really worth the hassle though!