MOPED ARMY

So are you saying I don't need to blow-dry it? Is shaking out the water well and spraying with WD-40 and using gas-line antifreeze sufficient to get the water out?

Didn't use the hose before, but I will now...

any sort of alcohol (gas line anti0freeze) will absorb the water. isopropyl (rubbing alcohol is cheap). when i did mine i just washed the inside out with mineral spirits (not an alcohol, but it still mixed with the water). i like parentheses. but really blow drying is what is rusting the metal. wash it out and fill it with premix right away

I've used both Phosphoric and Muriatic acid to clean tanks. Muriatic is a lot cheaper but Phosphoric acid does a better job.

Fill that tank with pre-mix and a little gas line anti-freeze ASAP.

Behrs Concrete Etcher and Rust Remover in the paint department at Home Depot. Comes in a black plastic gallon jug.

I let mine sit overnight, a few hours would probably do it. The rust reacts with the acid and forms bubbles, so when there are no more bubbles in the tank, you're probably good.

There's an old post from MoPedLar that does a great job of describing the whole process.

Phosphoric acid isn't as nasty as other acids, but you should wear gloves and goggles and stuff. When you're done with it, you can neutralize it with baking soda.

Make sure you only use around 8-10 ounces or so and the rest hot water. You don't want to use full strength.