Early 70's did firewood and sold some shale used as facing material.
Decent money in scrap catalytic converters but with all the recent thefts its getting difficult to sell them.
If you have gold it's a good commodity, everyone recognizes gold. Some of the issues you're going to run into are finding an honest refinery with decent refining fees.
If your buying scrap gold jewelry, just because it's marked 14k, the law allows the manufacture to be off plus or minus 1k.
The attached book, Testing Precious Metals has some good advice for the buyer.
Spreadsheet for buying Karat gold.