Cvett originally posted his tank was pretty clean inside but since the subject of using phosphoric acid to clean them has been discussed I wanted to relate my experience doing this.
I could see a little rust in my tank and large dark areas on the bottom. I was using a Jasco phosphoric acid product on my body panels and it worked great. I poured a couple of gallons of slightly used solution into the tank and let it sit for a couple of days turning it. I ended up with a horrible gummy mess still attached to the bottom of the tank.
Searching the archives inspired me. I had a tractor. I had gravel. I had a worse mess. The rocks were stuck in the gumbo despite many minutes rotating on the tractor wheel. Getting all those rocks out was not fun. I was finally able to clean everything out by sacrificing my last 2 gallons of really good carb cleaner.
Despite ending up with a clean, rust free, non-leaking tank I went with a new one. The peace of mind was worth it.
Chuck
