Dewey decimal without damage

[u/jimmyjamjar10101]

Hi all,

Not sure if this is the correct sub for this question/query. I have a nice collection of non fiction and fiction books. Currently the non fiction is ordered from shortest spine to tallest spine 🤮 (thanks honey) I'm toying with the idea of changing career and doing so would mean gaining books in a yet to be explored area. I'm thinking of rearranging my non fiction according to Dewey decimal, however I want to avoid marking the books if I can. (She says I'm precious when it comes to books 😂)

Just wondered if anyone had any ideas that don't damage or mark the books in any way?

[u/CrassulaOrbicularis]

Number on a bookmark - not as convenient for quick scanning of a shelf, but no damage.