Can you put a pencil in sifrei kodesh as a bookmark?
Per this site, you can leave a pencil in as a bookmark only, but not if it’s to guard your Sefer
I would imagine the only issue would be not hurting the binding if you place the pencil near the spine and close the book on it. (Speaking from sevara as opposed to any halacha I am familiar with).
I would be curious as to where the halachos of kavod for sefarim are written (aside from stacking order) if anyone knows.