Just a quick update. I decided to go with the white vinegar approach for my rusty gas tank. So far I filled the tank with about 5.5 gallons of vinegar. I’ve done nothing else. It’s been soaking for 48 hours now and the results are looking great. Most of the rust has loosened or lifted away. Im going to let it sit for 2 more days then flush it all out and neutralize the residual acid with baking soda. I’ll updates picture tomorrow.