Slick!
How did the soldering gun demag? I remember using one of those...
If you remember, the tip on the gun is in the shape of a distorted loop.
With the gun off, insert the tool in the loop but not touching the loop. Turn the gun on (you may feel the tool vibrate at 60 Hz when you do), then slowly withdraw the tool to a distance of several feet from the gun before turning it off.
The 60 Hz field around the tip scrambles the magnetic dipoles in the tool, corrupting the alignment that made the tool magnetic.
Folks have replaced the supplied tip with a larger loop of heavy wire in order to accommodate larger tools. I haven't tried that because I have the bulk tape eraser for bigger items.
The rotation of my tool by the Dremel mechanically creates an alternating field so it's doing essentially the same thing as the soldering gun, except doing it mechanically rather than electrically.