This may be a dumb question, but can someone tell me what these dang spots might be on my paperbacks? They're not down on the pages of text, but if you close the book and look at the side and top edge, there are a bunch of little yellow and orange spots.  Nothing else is wrong with the books, so I really wanted to post them, but if this is something that will get me whaled on, they're off to the freebie box. 

Thanks!!

OK-I can't see it so I could easily be wrong-but it does sound like mildew or some other biopredation.  Foxing, an oxidation of organic and iron impurities left in the paper, generally appears in the paper, not on the outside edges.  Also, foxing is relatively uncommon except in much older books.

Can't tell without a photo, I've got some older paperbacks that have spotting like you described on the page edges. I think it's just a breakdown of the dyes that were commonly used on page edges. You rarely, if ever, see dyed edged these days. I have tons of older books with orangey/reddish edges.

I hadn't thought about dye breakdown.  They almost never dye edges anymore...

I have some older romances that have that yellow dyed edges and there is some changing of the color on them.

This is foxing: http://www.abebooks.co.uk/docs/HelpCentral/Glossary/images/foxing.jpg

How interesting...I was reading a book that mentioned foxing today and wondered what it was :)

bumping up Chris B.'s link to a pic of foxing.

funny you should mention dying of page edges.

I have seen five new books released in the last two months with this. One  was The Black Book, with the page edges dyed black. The others I cannot remember the titles but one was short stories which one was titled geese in the wind. :)

I think it could be coming back into trend.

I would see if you can carefully scrape the spots off.. if you can then its something growing on the pages and shouldnt be posted.

I just came across the first mass-market paperback copy of "Wicked" that I've seen - It's edges are dyed bright green.  :-)