Yes, I know that. Thought it might be implied in my post. But the funny thing about my case is that the box had been used already to send it priority mail (with the proper postage). It had all the markings on the old outside that it was used properly -- addresses, return address, canceled stamps, etc. So rather than throw the box away, I turned it inside out (and I think there were no postal office marking on the new outside) and used it for parcel post. You'd think Congress, the USPS, anyone, would appreciate my recycling of it. Al Gore (idiot) would.
Robt.