Modern Vespa

Looking for best way to clean the inside of my tank. It sat forever with fuel mix. Drained and checked - no rust but the bottom around the tap and about 2" up where the fuel sat is a caked on layer of crusty oil. I scraped some and it's not rust, guess gas evap and left some caked oil (39 yrs sitting).

Looking for best (easiest?) way to scrape it out... will something re-activate the oil and take it back to liquid state...

Thanks for the experienced answers to follow...

Well gas will reactivate it, but I don't think you want to go that way. I usually take the tank out, take off the petcock and gas cap, throw a handful or so of nuts and bolts I have lying around, tape the openings (duct tape or stronger), wrap an old blanket around it and put it in a clothes dryer on no heat and tumble it for a while. It helps if your lovely is not around. If the noise bothers you, turn up the stereo. Of course you can do this by shaking it like you got no brain, but it is not as much fun. When you are tired of this, dump out the bolts and pour in some hot soapy water.shake it and rinse out good and let it dry.Or you could "borrow" your lovely's' hair dryer for drying it out. Maybe you should just let it dry on it's own, that last bit could get you in trouble.

I've heard other people suggest the same method as Tierney, so will probably try that on my GTR rank that needs that treatment

I second Tierny, but would put diesel in it instead of soapy water

I just did this last weekend. The humidity was so bad that it developed surface rust within hours after cleaning. I redid it and sloshed around a coating of 2T oil to keep it from rusting again before I could reinstall and fill it up. We'll see how it goes.

Here's what I've been doing. Get some arm and hammer washing soda mix some with water. Fill the tank with it. Then make an electrode out of a cloth hanger. Stick the electrode in the tank be sure it is not touching any metal. Hook a battey charger up to it positive on hanger neg on tank. Turn it on lowest setting around two amps and leave it for a few days. When you come back dump out the water and behold a nice shiny tank.

That's cool 318.

Buy 1kg of small rocks for aquariums, remove the tank, put the rocks inside de tank with a little bit of gasoline, shake it a lot, remove the gasoline. To the same until the gasoline looks clean and after that remove de rocks.