YouTube is your friend here. I think even NileRed has a video on it.

Edit: here you go: https://youtu.be/ASQCa7mfjVo

He does it with PCBs in one and ram connectors in another, but mentions the process is essentially the same for everything else including CPUs. I'm not sure what the economics of the acids he uses versus nitric are, though.

Please, if they're not already crushed, find a classic collector to give them to. Most things from the gilded age (heh) have significance as antiques.

There's nothing more disheartening to a classic computing enthusiast than to see a historically-interesting minicomputer destroyed by goldbugs.