Fintail,
Yes, the magnet goes on the outside end, and magnetizes the whole plug. These magnet are incredibly powerful. You would have to see to believe it.
Test it out by seeing how magnetic the inside end becomes.
This will not magnetize the pan because it is aluminum.

jbaj007 is correct, of course. Both poles attract ferrous. I was thinking of magnets repelling each other. You can chase one rare earth magnet around a table by placing a second magnet underneath. If you flip the magnet under the table, the one on top will flip as well, just like magic. Amaze the kids!

Toby, I would think anything that made it as far as the filter would probably get filtered out pretty well, but I have an open mind on the matter. Might trap the smallest of particles that would normally pass through.

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1986 300E 5-Speed 240k mi.