Heres the process to end your day of nitro running motor wise.
1. After your car runs out of gas when running it. Bring it over to you and apply the glow starter and try starting it for a little till the car completely stops firing at all, it will probably change sound a bit too and clear out. You can even put your finger over the exhaust to help direct more pressure into the tank to clear it out more. I sometimes clear out the tank this way. I remove the fuel line , apply my finger and put it on the starter.
2. Then make sure your piston is at BDC. A simple mark on the flywheel while ensuring the piston is a BDC beforehand makes this easy to check.
3. Remove glow-plug and apply a couple of drops of after-run oil and then turn the motor over via the starter/pull-start a couple of seconds. Stopping it again at BDC.
Then tilt the car to the side and make sure all the oil is out of the pipe and wipe that off and your good.
-- If you leave even the tiniest bit of fuel in the tank it will form water vapor and could cause rust in no time. But it shouldnt rust, I would figure whatever they use in a tank should be rust resistant or something as nitro fuel will bring on water.
Bottom Dead Center. Piston is at the bottom of the cylinder.
That fuel tank has been around for years, Kyosho has used it in vehicles for a long time. I don't think its steel or any other ferrous metal (it won't rust). I have cut many off, removed it and replaced it with a screw. It always leaked.