I'm sure that everytime I go to the scrap yard I don't get the maximum value for what I had. This is mostly because I failed to properly identify the the less obvious copper, brass. etc. contained withing the items I scrapped. For example I often find old comunication equiptment such as 66M Blocks. I never knew that these blocks contained easy to extract tin plated copper clips until someone at the scrapyard told me when he saw me tossing them in with my light iron.
If anyone else can think of some other sorces of valuable sorces of metals often overlooked please share them..... WE CAN ALL USE THE MONEY