When I worked for a plastic place we would custom make parts and pieces for all sorts of companies. Custom van company, boat co. just to name a few. My job was to run the grinder (not really a grinder), where we had a conveyer that would feed into the input of the grinder so you had to feed it at a certain speed. It was blown up and across to the other side where we had gaylords lined up. When one got filled we'd transfer the overhead hose to the next gaylord while covering up the other one with a lid. They were weighed and usually ran between 800 -1000 lb. That stuff was granulated in a hammermill affair and reused to make the new plastic. What I was feeding was messed up parts, or the outer edges of the parts where they would router out the parts they needed. They were using the ground stuff inhouse.