Jake in Dallas

Hi,
I'm a sixty year retired vet who has been interested in starting a scraping business for the last couple years. My son's neighbors are in the gutter business and they got me interested when my son was making a few hundred bucks a month taking their aluminum gutters to the scrap yard close to our house.
I would like to make more and am willing to do the work. I am wondering and looking for feedback from members of this forum that if I walk into businesses on a regular basis is it too late or is there tons of business out there.
Also, do I need to offer to pay people for their scrap or appeal to a 'cause' based approach.
Jake