I see plumbing trucks at the scrap yard all the time. But there is no harm in asking what they do with there scrap. As prices are still down you just might get someone interested. As a business they want to control costs. You could market it to them this way...
Due to low scrap prices they may want to not spend there labor scraping these materials any longer.
They can still be a "green" company by having you do this service for them.
They can save the cost of disposing the items in there trash (if they were not recycling) if you were to help them they may need less trash pick up.
And even if they say no the person or persons you talk to might have contacts for you to get other jobs or even there own junk at there houses.