There is a vast amount of pianos that are unwanted now a days. They are very expensive to repair, tune and costly to move. With all the electronic pianos on the market and the features they offer who wants to bother with grandma's old Baldwin.
I don't think there is enough money to be made to offer "free piano recycling" but if you want to scrap a few to get a feel for the market perhaps charging $200.00 to pick up and $50.00 for drop off recycling might be worth the effort.
Here is a newer Kimball piano we just disassembled, it had one solid piece of oak at the top and the rest was laminated pressed wood. Most of the older pianos have some solid woods like walnut and others have more valuable woods including extinct species but most consist of laminates. The sound board is the best for recycling but is often the most difficult to reclaim. The ivory keys do sell on eBay and the older piano benches can bring up to $150.00 plus.