I talked to the person that was filling my tank once about this. He said that he's refused to fill tanks that looked very rusty. That was his criteria. I've cleaned, and painted every MH LP tank that I've owned. Including the 73 that I'm selling. Keep your LP tank well maintained. Replace the 2 stage regulator every 10 years. DO NOT install a single stage. I love Linda, our GMC, and myself. Money well spent. Bob Dunahugh 78 Royale