Double Recycling with Mailing Items

I mail a lot of books to my relatives. So I am perpetually saving every box I get my hands on in order to ship books in them later on. But...those boxes, being used, all come to me with giant shipping labels on them, and bar codes that somehow have to be defaced, removed, or made invisible before I can send them on to their new destinations.

I have discovered that if I take old envelopes (such as those outer envelopes from my utility and mortgage bills) and write the recipient's name and address on them, then attach them to the front of the boxes with tape, they are big enough to cover the previous shipping labels without me having to scribble over anything futilely, or trying to rip them off without damaging the box. If I'm using a big box, I will have to use another scrap envelope above for the return address, but I find it works very well.

That works well.  In the past, I have just used a sheet of printer paper folded in half.

What I have seen on a lot of packages that I receive is that black marks-a-lot works too.

Many of the packages I receive use the services like USPS Print Click-N-Ship Online Postage.

I reuse the envelopes that come with junk mail to make shopping lists and to-do lists.  Some of them can even be used to mail stuff because there is no writing on them.

When I sold on eBay I reused padded envelopes to mail items I sold.

I always just detach the glued edge, turn the box inside out, and reglue.