I have a 1951 International pickup that I restored. The gas tank was really rusty inside, so I removed it and rattled rocks around in it to loosen the rust, then flushed it repeatedly. May as well not have bothered. The system has a filter just before the fuel pump, and another at the carb inlet. The pump filter was coarse enough that the carb filter plugged up within 1000 miles, and I had to clean or replace it several times. Then I realized that the contaminants were all rust particles, and since the pump filter is a plastic canister, I taped one of those rare-earth magnets to the outside of it. Both filters stay clean now, since pretty much all of the junk immediately goes to the magnet and stays there. I just pull the filter out every so often, take the magnet off, and blow it out. A guy could make his own plastic canister, no filter in it, and put it upstream with that magnet on it and leave it for a long time. Next idea is to put one of those magnets in the tank, on a wire that I can reach to pull it out in about a year. The rust will collect on it as the fuel sloshes around. One more idea: There's a sloshing sealer used in fuel tanks and aircraft floats to seal them. This stuff would encapsulate the rust and lock it up almost forever. Got to have the tank off, though, to coat the whole inside. Randolph makes it. See
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Dan