While browsing my shelfs I found several old books were the paper slowly dissolves due to being printed on non-acid free paper. The one which I would mostly miss is a 3 volume work on mechanical engineering from 1919. It is quite large and will take a lot of time to archive it digitally.

To see whether it can be done in a reasonable time, I did a test with a textbook on physics, which apparantly was used by my grandfather more than hundred years ago. It is a thin book, thus I used a standard flatbed scanner. That would not work with more voluminous books, but here it worked reasonable well. The paper was anyway short of turning unreadable, thus even a bad scan was better than no scan at all.

If you are interested in a German textbook on physics for schools from 1902, you may read or copy it from https://grundzuege-der-physik.eifzilla.de.