To remove the can tops, I use a big red "Master Heat Gun" that is used
to strip paint off your house or your interior mouldings.  Just set it
up on the desk pointing up, at the 500 deg. F. setting.

Hold the valve block (by the elbow) in front of the hot air blast for
6-10 seconds.  Then take it out of the air stream and use a flat blade
screwdriver or a dull knife to squeegee off the burned shellac.  You
should be able to use a needle nose or side cutters to grip the metal
and lift out the can.

D.L. Bullock
www.dougbullock.ws