When they drive the armored vechile into Casanova's mansion, they turn on the magnet so the guns are taken...but why doesn't it attract any of their weapons such as the shovel, forks, and those many weapons made by Dr. Heller?
Well, they would have known that they were going to use the magnet, and Dr. Heller (the incomparable Tom Waits) is a pretty clever guy, so maybe they magnetized their tools and weapons with a like polarity of the magnet. Magnets only attract opposite polarities.
Electromagnets will generally attract any ferrous (iron-based) material, regardless of magnetic charge. My SOD for this scene was that I imagined the good doctor had machined the weapons from non-ferrous materials, such as chrome and nickel, aluminum, etc...
Aren't the Blue Raja's silverware...silver, since he gets the expensive set from his mother? I suppose it could be a cheaper iron-based version, but this seems unlikely. Still the Shoveler's stuff sure looks ironic (pardon the pun).