This may sound dorky, and it would take some work and it's kind of dirty, but collect aluminum cans from friends and co-workers. The current rate is $1.25 per pound in the State of California.

I belong to a local service club and we operate a weekly aluminum redemption center. As part of our service, we work with youth groups and other people doing fundraising and we give a premium for large amounts of cans. For instance, depending on our redemption rate, we may offer upwards of $1.40 or so per pound, if the group or person has brought in 50 pounds or more. Usually they bring in much more, and it can add up really fast. Just a
thought.

KD