We must be about the same age. I was a junior also during the first earth day.
Our school decided to load up a few buses and drop off groups of four with bags to pickup roadside trash.
It was a beautiful spring day and the legal drinking age had just dropped to 18
The bus driver made the mistake of dropping our group within walking distance of a convenience store.
The trash we turned in at the end of the afternoon were all fresh empty cans.