Just a note about aluminum recycling. Humans tend to trash things instead of recycling. Out here in the desert where people dump things I have noticed old steel cans rusted to nothing mixed with aluminum cans which seem to not degrade over time.
Arguably if you are worried about the environment and account for human laziness steel cans are better for the environment IMO
I've read around 75% of the aluminum ever produced is still in use today. If you machine a new surface on aluminum, it will form an aluminum oxide layer in a matter of hours. I believe (but am not certain) this effectively prevents it from degrading the way steel does over time.
Aluminum can recycling rates tend to be higher in states that offer deposit programs. Back when they were getting introduced in the 80's, $0.05/container had a lot more buying power than it does today. It's enough of an annoyance now, they'd be best off eliminating it or increasing it to ~$0.15 or so. Or since this is HackerNews, maybe we could use block chain technology to verify each can is properly recycled and reimburse with bitcoin.
A classmate of mine in college made all of his sculptures out of plywood and Bondo, reasoning that they were likely to last much longer than anything made out of metal due to having no scrap value.
Arguably if you are worried about the environment and account for human laziness steel cans are better for the environment IMO