Whenever I see a discarded pencil, I have to pick it up. When I see a discarded mechanical pencil, I pick it up, give it a shake. If it jiggles, it has graphite, so I keep it. If not, I pitch it in the trash. Most of the pencils I find are still good.
Odd. This is how I get most of my pencils. I didn’t even have to purchase them anymore.