A month in a sealed box with charcoal should help me determine what to do. Jasmine tea packets and tea tree oil cotton balls didn't do the trick.

If charcoal doesn't work, well, into the garbage it goes, even though it's Pleiade.

I tried baking soda on a book a while back but it got into all the pages and I couldn't get the dust out.

Weak bleach and sunlight was tried last summer and didn't do much. This is why I think it's a lingering smell issue rather than a spores/mildew issue. I left it in the sun, I froze it for two months in the freezer in a bag filled with silica packets. If it were active mildew/mold, that should have killed it. No, it's just a smell. I can't smell it at a distance but putting it up to my nose I certainly smell it.