The best way to clean a rusty gas/petrol tank is to use muriatic acid. Muriatic Acid is generally available from your local hardware store but WARNING it is a acid and is extremely dangerous to work with. Read the label carefully and follow the recommended handling instructions. You do not want to get this stuff on you. Wear long gloves and a long-sleeved shirt. You also don’t want to be breathing it, so do this OUTSIDE in a open airy environment. Don’t get it on any chrome/alloy pieces – it will damage them.
Cleaning the tank is as easy as the following-
- Drain the tank of fuel
- Remove the tank from the scooter and remove the fuel tap and cap.
- Get inside the tank with a wire brush and clean out as much as you can.
- Fill the tank with a hand full of nuts and bolts with 1/2 cup of gas/petrol and give the tank a good shake (remember to put the cap back on). This will loosen any built up grime.
- Give the tank and good wash with warm water.
- Plug the bottom of the tank with rubber duct tape. Fill 1/2 way with hot water. Add 1 liter of muriatic acid, then fill to the top with hot water. Don’t use the gas cap as the acid will eat the chrome. If you fill less, occasionally plug the top and turn over to get everywhere.
- Leave the acid to sit for a few hours.
- Drain the tank, depositing the liquid responsibly (with a local chemical depot if you have one). Rinse the tank out with water a few times.
- Clean out any remaining/semi-loose bits. Rinse out with gas.
- Add fuel tap, install, and fill. Don’t leave it sitting or it will develop some surface rust.
All done your tank should be like new.
