In the optics you will find what looks like a three-legged transistor with a domed, clear top. That piece and its legs should be gold plated.
My board buyer gives me the same price for the circuit boards from printers as he does for motherboards.
The motors sell for more than scrap steel price at your scrapyard due to the copper content.
Many will have a stick or two of memory which you can sell outright or process yourself.
I get $3.00 each for used toner cartridges in the form of a quarterly rewards card from Office Depot. They have a monthly limit of 20 cartridges and I have a backstock of over a years worth of cartridges stored. It makes for a nice $180 shopping spree every three months. You do have to spend at least the equal amount of your rewards to be able to get them.