A Question for the Book Repair Savvy

Reader Jon Hendry asks the following question about preserving old gaming materials:

My 1st edition AD&D books, and other items, are definitely yellowing from acidification. They ain't gonna last forever, and while scanned copies are an option, I like having them as physical artifacts as well.

There are deacidifying sprays you can get, but those would probably work better for, say, maps or short modules. I'm not sure how to go about deacidifying something as long as a DMG.

Anyone out there able to offer any advice or practical tips about this? I'm curious to know the answer myself, since, like Jon, some of my older gaming materials are starting to look yellow and brittle.