Basically what it all boils down to is:
It is not worth the effort trying to extract the gold from CPU's. You would need hundreds if not thousands to make it worthwhile.
Also the chemicals and acids you have to use are far too dangerous to be doing this at home/by yourself without proper equipment.
The next best/easiest thing would probably be just to send them to a recycling plant that recycles electronics and get a few bucks out of it.