Reuse envelopes as scrap paper

I keep a stack of old envelopes on my desk at work clipped together with a paperclip. I use them as scrap paper by writing on the back, provided that I shred anything that has an address (for privacy reasons) on them.

For larger envelopes, I often tear down the edges and flip them inside out. They make great scrap paper that way, but I also use them to line things that easily become oily or dirty.

For envelopes that are pristine and have no address at all (i.e. the kind that you get from credit card companies, taxation people, or alike), I typically use them again for sending out my own mail. We found some labels in our storage that we could stick to the envelope, effectively blocking any unwanted addresses. Voila, a free envelope.

We're saving the environment, one envelope at a time.