Ok I have an ex-library book I picked up used.  The book is 21 years old and on the inside cover where the flap sits there are large yellow residue marks on the dust jacket and on the inside cover.  You can tell that it is because the flap used to be glued down to the cover but over time the glue wore off and now there are just the yellow marks on both.    This is on both the back and front flap of the DJ and the inside covers of the front and back of the book.

Just want to see whether I should post it or offer it as a freebie with another order from my shelf.  This book is WLed by 3 people.

but warn the folks first before so they can cancel -- odds are at least one of them will want it, and it is technically postable, IMHO.

it sounds like the book is postable to me, you could always offer it as a freebie if you are unsure or if you post it, offer the receiver another book off of your shelf if they so desire it.

if you are going to PM the people to make sure the book is ok, make sure you give them a day to reply by so you don't miss the mailing date....and choose the furthest out mailing date

For myself if that was all that was "wrong" with the book, I see no problem in posting it.

Matter of fact, I have an RC that I only want HB books with dust jackets,

so I would be thrilled to get a 21 year old Wishlist book, with a dust cover.

It sounds postable to me too.  If it just bugs you for aesthetic reasons, you could get a clear mylar cover (like libraries use) to go over the dustjacket and tape it in place with a piece of scotch tape looped over the top and bottom of the front & back cover.  If the old adhesive isn't visible unless you lift the inside edge of the dustcover, this would keep the dustcover flat and in place, and if you make sure the tape only comes into contact with the mylar cover, you won't risk damaging your book or dustjacket either.  The other thing - most adhesives used to keep a dustjacket in place don't penetrate very deeply into the paper lining the inside of a hardcover book.  It could even just be old two-sided tape.  You can probably sand it off with some fine grit sandpaper.  The back side of the dustjacket will probably be another matter, since it's too thin to sand very much without damaging it.  If the spots are still slightly tacky to the touch, put a piece of scotch tape over them.  Since dustjackets aren't a PBS requirement anyway, I doubt that an ugly spot or two on the back side of one is an issue in whether the book is postable or not.  As long as it isn't mold, food, or anything equally disgusting, I wouldn't be too concerned about how it looks, and putting a couple of pieces of tape over those spots - if they're at all sticky - should take care of it.