I've seen a couple of comments on the 'net that it's possible to mass-remove components from a circuit board by heating the whole board (in an oven, or over a heater) enough that the solder will melt, and the components will fall out if the board gets a sharp tap. This sounds like both a very bad idea, and a very bad idea, at the same time.
- How hot would the air around the board need to be?
- At what temperature would components start getting damaged?
- What components would get damaged first?
- Is there a reasonably reliable and safe way to do this? (I.e. one that doesn't require melting lead in an oven that must later be used for cooking)