Not sure if I read it on here but I needed to de-rust the inside of a fuel tank so I put 2 Gallons of pickling vinager ( 9 Litres to the younger members) in the tank and left it for a couple weeks. Cleaned it out tonight and it`s done a cracking job. After swilling it out I have swilled it with diesel and left a couple of pints in it ( Just over a Litre ) .
I did a tank clean with vinegar brought to boil added some baking soda and used electrolysis. Within an hour the tank was clean and rust free. I preserved it with a small amount of 2 stroke oil.
Nobody really cares if you're miserable, so you might as well be happy.