A good quality packing tape is really worth it. 

I actually use the printed two page mailer for the small paperback books. For small PBs: I will cut up a clean plastic bag to go around the book, tape the plastic with scotch tape, wrap the two page wrapper, tape that well with packing tape, then tape over the address (as I have an inkjet printer).

For larger books (IE trade sized) I use the one page mailer and sturdy paper. (I personally use old maps as I have a pile of them.) Again, plastic. Again, packing tape. Again, over the label.

I generally use an old bubble mailer for hardbacks. The corners always seem to get damaged on hardbacks. I will fold the mailer tight around the book so there is no wiggle room.

I think the most important thing to say is the never dos.

Never use press and seal plastic as it leaves the book gummy.

Never re use the priority mail free mailing material. This may cause the book to arrive postage due.

Never use scotch tape on the outside. I do use scotch tape to hold the plastic closed. But scotch tape comes off if there is any moisture. So I make sure to use packing tape on the outside.

Never tape directly to the book cover.

Never leave a book loose in an envelope. The sorting machines rip open loose envelopes all the time. Fold the edges down snug and tape them. Envelopes work fine. Just not loose flapping corners.

You've been a member for a while, so we could probably answer your question better if we knew more details of what you want to know .... if you were trying to improve your own wrapping, for example, or maybe had a question about the way someone wrapped a book that you received.

In any case, the PBS recommendations are here http://www.paperbackswap.com/help/help_item.php?id=50

They don't require a plastic layer or any type of waterproofing, for example, but many members find it is better to use something to waterproof packages, whether that is by using something like plastic wrap around books before they are packaged, or by using a waterproof wrapper.

Many members would recommend boxes or bubble wrap for hardcovers, but there is no PBS requirement to do so.

Hi,  I didn't write more in my original post, because either my computer or my system was not letting me type in the text box.  Then I accidentally sent it. 

The reason that I am asking is because I received a book with liquid damage on the outer edges of the book.  It is brown like a coffe stain, but could be dirty water.  It is very noticeable.  I marked it damaged by sender.  The sender claims she sent it in great condition when she sent it.  It is possible it was damaged in the mail, but the book was not wrapped in plastic.  It was wrapped in a heavier cardboard post office envelope.

Do books have to be wrapped in plastic, or is that just a suggestion? 

I feel badly because it is a pricy book (homeschool curriculum), however, I was planning to repost if I didn't like it, but now I can't. 

Thanks for any advice!

what's a bazaar and where is it?

Charles -- The Book Bazaar is one of the PBS Discussion Forums (the 8th one listed) where members can advertise deals, sell credits, offer unpostable books, list multiple WL books, etc.

ETA: Be sure to read the Red Sticky thread on how to use the forum.

Does the packaging show any signs of the damage?