That might work for the PCBs, though what will it do to the components?

However, what I really need to remove it from are special HeNe laser tube
assemblies. Not the common laser heads, but ones where the tube is totally
surrounded by the stuff as well as in front and back. So, the tube will
still be stuck inside surrounded by brittle hard stuff.

Thanks for thinking about it!



That sounds like a real pain. If you can use a long drill to drill a
tunnel parallel to the tube, you might be able to saw around the tube
with some piano wire.