[SpikeDad]

They need to be frozen under vacuum. Otherwise the moisture in the air will damage the books as they're frozen. Not standard equipment libraries have at their disposal.

Most libraries just isolate donations and if there's any insect activity they're discarded. Only special, valuable books would be sent out to specialized companies that do the freeze drying process.

[Baeocystin]

Why even freeze or poison if you're pulling a vacuum anyway? Wouldn't that be enough?

[SpikeDad]

No. There could be eggs which would survive a vacuum.