Cleaing out a Model A gas tank

[KGBnut]

You are absolutely correct, pure ferrous oxide is not ferromagnetic, but the stuff I have found in my tanks usually has a fair amount of unoxidized iron...and that sticks to magnets. On some tanks I have lowered in a bunch of ring magnets on a rope and they come out covered in rusty bits.

Don't get me wrong...this is a temporary band-aid and you are much better off to have the tanks properly cleaned and repaired, but this technique has gotten me home.