Cleaning the insides of old fuel tanks

[Alex Blair (RIP)]

Originally posted by Keith Webb
Can anyone suggest a solvent which might dissolve this tar?

Hi Keith..
That sludge may be water soluable as opposed to oil soluable..Try an intense mix of water and washing soda..That will do both...
Scrape some into a dish and add soda and water and see what happens to the goop..If it softens or disolves it,make up a intense mix for the tank and let 'er soak for a day or two..
Hy pressure wash out the sludge.