I know it is a big no-no to use the free priority mail boxes or envelopes for media mail.  But what about recycling these?  I have some perfectly good boxes for mailing books, but they are the official white priority mail boxes with tons of "priority mail" stickers all over it.  Are they really not recyclable?

You can recycle them to send Priority mail, but not to send Media Mail.

You certainly can recycle them in any way you choose, EXCEPT to mail in other than by priority mail.  I have a lot of things stored in Priority mail boxes in my home. 

Thanks for the info.

I had one arrive yesterday that had been wrapped in the PBS paper wrapper, but they'd used several Priority Mail stickers as tape on the inside layers.  You could clearly see them through the top paper of the wrapper (which they sealed in scotch tape.)  I'm pretty surprised that it made it that way, since the P.O. seems to be getting stricter about media mail.