Thank you both. Use of ground rods (with heavy cables) is good advice for diverting strong waves through common frames.
Steel wire mesh/screen (for those of us who can’t afford copper or gold mesh) insulated from both the outer case and the object to be secured can add an extra layer. It can also be used around insulating seals (better if completely around the case with lid seals). Even aluminum foil, though it’s not the greatest conductor, insulated on both sides, may help a little as an extra layer for small items.
RF waves are a little different in some ways from surges through lines, in that the tighter and more conductively continuous the case, the more secure against RF waves (only guessing from compliance with FCC rules in past computer integration).
Yes. In further considering a little knowledge about RF pulses, it might be important to seal (with steel or at least tightly with aluminum) holes and gaps in the body of a vehicle. An RF pulse is a bit of a different animal in some ways than a line spike. Think of sealing your vehicle body from radio signals with a very wide band. ...similar in effect. If you can’t contact anyone from a cellphone or personal, two-way FM radio from under the closed hood of the vehicle, it’s probably pretty well done. ;-)
Great idea. Remove the guts, ground the chassis. Contents in the plastic cooking cavity are shielded from the conductive frame. Clever.