I have numerous contracts/accounts and here's how I do it:

Pickup once a week at a set time. Account A I pickup Monday at 9am, Account B Tuesday at 10a, etc. I do not pay for ferrous, but do pay for alloy wheels, batteries, and large quantities of aluminum such as clean cast or extrusion. Usually 40% of yard price.



My contract is pretty simple- I get all scrap on premises and I detail the types of scrap(this varies by account). It specifies what day and time I will be there and if I need to come a second time per week then they just give me a call. No early termination fees or anything like that, but I do hand out freebies on occasion such as $25 gift card to a local restaurant, couple 12 packs of beer, etc. That goes a LONG way!