Easyist way to remove all components from circuit boards

Consider using a Solder Pot -- like in this video:

For the SMD chips, I would use a vacuum SMD pick-up tool, like:

JIAN YA NA SMD BGA Vacuum Suction Placement Machine -- which I've never used, so can't vouch!

There are also simple un-powered "pencil" style ones that I have used, but they are of dubious effect. My soldering station has a powered vacuum placement tool that works quite well, but the whole thing was around $100 at Circuit Specialists.