How Can I remove Mildew Smell from Older Books?

We have used bounce dryer sheets before to remove mildew and smoking smells from books and it seems to work well. Depending on how strong the smell is, it might take up to a month, but if you place dryer sheets through the book and close it off in a shopping bag it should work. 

Sophia has a course on how to deal with deodorizing books. It's only 99 cents.

I would be really careful with the dryer sheets. (Before I explain why just feel the need to point out that I'm actually a costumer by trade that ended up with a library job. Long story, but that's where my real expertise is.) Dryer sheets are actually very thin pieces of fabric that are coated with fabric softener. If you rub an unused sheet between your fingers, you will be able to feel it. Then rub it between your fingers some more. Then set the sheet aside and rub your fingers together. Do you feel that stuff on your fingers? That's the fabric softener. Now do your best to ignore it, see how long you can go about your business before you feel the need to wash it off your hands, and you will have a pretty good idea of just how well this stuff sticks to things. That is what you are getting on your books if you are using dryer sheets on them.

Here is why this is a problem:

Lingerie experts (Yes, that's a thing. And yes, I giggled when I found out too.) will tell you not to wash your bras, panties, and other delicates with fabric softener in order to make your garments last longer. The reason why fabric softener works is that it very gently breaks down and weakens the fibers of your clothes. If you are washing very heavy duty fabric like denim, this doesn't really matter. But if you are washing something that is already delicate to begin with, you don't want to weaken the fibers even more.

So what do bras have to do with books? If you are trying to preserve something for a long time, you don't want to weaken the fibers. Adding a chemical whose whole purpose is to weaken fibers seems really risky to me. Plus if you have ever washed a load of clothes with fabric softener that didn't rinse well, you know that it's not coming out again until you wash it properly.

On a side note, watered-down fabric softener is a paper aging technique used in the theatre for prop creation. Yet another reason why putting it on a book makes me nervous.

As I previously stated, I'm a fabric person first and a book person second, but I would use Sophia's recommended techniques from her course. She has the expensive, framed papers on her wall. ;D

Sorry to downvote the dryer sheets but Sarah is correct. Dryer sheets placed between pages will transfer non-archival product into the book that will destroy it over time.

Another note on removing smell. It is nearly impossible to actually kill mold or mildew without completely taking the book apart and treating each page. This is excessive and too expensive for most books obviously. Mold and mildew spores are insidious and microscopic and ultimately if you can replace the books you should strongly consider tossing the mildewy ones out. (I know it is very sad.)

NOTE: The ways that people attempt to kill the mold or mildew can be just as destructive as the mold itself.

• The Sunlight Attempt: You can prop up your books in an indoor sunbeam and turn pages over days exposing different surfaces.
  •      What can go wrong: The sunlight could fade the colors of the cover or pages. If there is a lot of heat with the sunlight it could also reactivate glue or dry out glue. It can also warp the pages and boards of the book.
• The Microwave Attempt: Short bursts of microwaving.
  •      What can go wrong: Too many things! You can actually burn your book pages or melt the glue or if there is foil stamping or other metal inclusions. (Some older books are staple bound and the staples are invisible unless you dis-bind the book.) You could cause sparks or even a fire or an explosion!
• The Bleach or Alcohol Attempt: Wiping watered down bleach or isopropyl alcohol onto your mildew may seem like a good idea. After all, we use bleach and alcohol to kill germs and clean things! But unless you can rinse it out of the pages you have just wiped a time bomb onto your books.
  •      What can go wrong: The acidity of these solutions will (over time) turn your pages brown and they will disintegrate eventually!