Cleaning Old Books

Hi! Librarian here (although I work mostly with kids, I did take a rare books handling class years ago) I'd limit the isopropyl to glossy/shiny surfaces only as it could destroy more porous materials. I'd add some kind of alkaline buffer- there are some commercial sprays you can use, this helps slow the acidification of paper, and some very soft brushes for dusting. Be careful with anything moldy- I work in a library in Florida and have seen first hand where a moldy book spreads the mold party to other books in close proximity. Also don't do mending with household tape or glue. Demco has some nice alkaline glues you could start with and you can learn more about "advanced" mending techniques. What kind of books are you collecting?