I'm trying to figure out why I have such a problem with stained books.  The stain is usually yellow and on the outside of the pages.  It doesn't appear to look the same as age discolaration and occurs much more randomly.  I see it on new books as well as old.

Has anyone else noticed this problem? Any idea what's causing it? I'm currently going through my entire shelf to weed out bad books and am horrified by how many I'm finding. I'm getting rid of the boxes I've been using for sure - anything else I can do?

Some books are made that way. Are you sure this isn't the issue?

Beyond that and barring the obvious of cat urine stains I would say oxidation.

Sweat maybe? Is it where the book would come in contact with your hands while reading?

If it's uniform around the edges of the pages, or if it's related to where the book was exposed to air or light, then it's normal aging and that is allowed here.

Made that way?  Oh, you mean books where the edges are yellow instead of white? No, this is definitely some kind of stain, on white pages.

It doesn't look like oxidation, which is browner and more regular in how it occurs.  It seems to happen anywhere on the edges - top, side or bottom. I suppose all of those might be places where the book comes in contact with hands, though I'd think if it were sweat, the pages would most likely have some roughness from liquid damage.

Perhaps just skin oil then.

If the color is speckled (mottled), then it's the grade of the paper. It appears in older books more often than newer books. There is nothing wrong with these books and it's natural aging.

However, if the color is uniform, it's because the books edges were subjected to flourescent lighting over a long period of time. I also find books stored near my window yellow very fast on the edges. I just don't know which is worse, flourescents or sunlight!

(If you don't like the look of the book, you can remove the yellow color from the edges of the book with a medium grade sandpaper.)

i had to through out a box of harlequin romance books b/c there were yellow spots on the edges of most of the books. i figured it was prolly cuz we had a really bad mice problem at the time. so i didnt want to touch anything that might have "mouse pee" on it and i didnt think anyone else would either

Eww, that's an unpleasant thought! Haven't seen any signs of rodents, though. And I think pee would cause more damage than just a stain, wouldn't you think?

I've seen those before, and bravely sniffed them.  Any I've had were completely odorless, which leads me to believe it's just the natural oils we all have on our hands.

Well, though the origin of the stains may still be a mystery, I have figured out how so many of them made it onto my bookshelf.  They completely disappear under the light in my office.  I was only able to see them this morning because I was using natural light.

They completely disappear under the light in my office.  I was only able to see them this morning because I was using natural light.

I'm so glad I did a search on this today! Yesterday I took some of my books out of storage to inspect and air out.  I saw quite a few books with the yellowness. I remembered the sanding trick so I grabbed a couple last night, and couldn't find the yellow. So this morning I was gonna post and voila saw it again. I thought I was losing my mind.   LOL

Is it possible that it might be caused by humidity levels where the book was stored?

Older and cheaper paper have acid in the pulp.  That's why there is often a notice on the copyright page about acid free paper.  The acid reacts to things like light, skin oil, and moisture.  This is one of the differences between HBs and bookclub HBs.

So if the book  has little yellow or yellow/brown spots on it, is it still postable?

Are they age spots?  Which would be due to the acid in the paper.  Then yes.  If it is mold, water damage, or food, then no.  I'll PM a person if the book has a lot of age spots.  But with older PBs, you aren't going to find books without them unless they have been in climate control.

These books with acid in the paper also yellow faster than acid free paper.  So light exposure will affect them more.