I have several paperbacks I'd like to post, but I'm not sure whether they meet the "good condition" criteria.   All are readable, without markings, water damage, missing pages, etc., but do show their age or wear. 

1. Some of them are several years old and the inside is fine, but they have grown yellow around the edges.
2. I have read all of them, and although the pages are not loose or separated, some of the spines are wrinkled or creased, the way they can be if you hold a book open on your lap.   I've noticed this particularly with mass-market paperbacks, where the quality isn't as good as in trade paperbacks.
3. A couple are slightly out of alignment as a result of being on bookshelves where they weren't tightly wedged in. So they have leaned, and are no longer perfectly square. 

I haven't found anything about this  in the official guidelines.  Are they postable?
I would not want to mislead anyone by posting a book that should not be posted; on the other hand, I'm not yet sure how worn or used a book can be or look in order to be non-postable.   So far I've received only three books, so I don't have enough experience to know for sure.

Thanks!

To my knowledge:

1.  Yellowing and foxing is fine (Foxing is like age spots)

2.  Spine creases are fine

...I am not sure about the alignment. 

It sounds like they are ok.  I usually go by the thought "Would I be mad if I got this" when it comes to an older book.  Sometimes the life of a book has to end somewhere down the line.  (Lately, though they seem to stop with me.)

Thanks, Karen. 

I'm not sure the "would I be mad?" criterion applies, as I'm pretty lenient about used books, and my expectations aren't all that high. If it's intact and readable, I'm ok with it.  In the short time I've been here, I've noticed that members differ greatly in what they expect to receive, so perhaps I'm over-cautious.

I can probably press the ones that are slightly askew under a pile of dictionaries (of which I have many).  I don't know how long it would take, but they might revert to square.

Nevertheless: Whenever some requests said books. I would accept, then send requestor a PM thoroughly explaining the condition of the book.  I tell them that unless they contact me saying ship, I will no ship. There are, in my experience, a rapidly growing number of very picky members who seem to expect all books to be like new. (I have had two complained about that were paperbacks over 30 years old. )  As it has been explained to me, PBS always takes the word of the recipient regarding condition, and you will wind up with a bad mark on your toothbrush chart.

I had a number of old out of print paperbacks that I posted.  I selected the last mail date and PMed the member about the age of the books,  stating that they were postable but very old, and offering to cancel.   Not one person did.   And I had the PMs on record.  One member had had the book on their WL for over three years.

In my mind, it makes a difference if a book is hard to find.  I'd be thrilled to find a beat up copy of an old rare paperback.  I'd be alot less thrilled if there were many copies available.  Or if there were more recent editions of the book.

Katherine--

If I have books as you describe, I'll post them if they are currently out of print.  If the book already has lots of copies in the system or is readily available elsewhere (due to being reprinted) I usually won't post them here.  I figure that most folks would be happy to get a readable copy of hard to come by books, even if the book isn't in the best shape.  For readily available books, I figure a lot of people would be disappointed to get a book that's shows more signs of age, so I won't post those.

That said, I don't post any books if there is anything at all (no matter how minor) that would make a book unpostable per PBS rules.  I assume that when people order a book from me, they want a book they can read and either repost or keep on their own shelf.