Fuel Tanks Cleaning?

[e21Keith]

I have three pairs of fuel tanks for my e21, just need to pick the best pair and clean them before fitting.

All the tanks have come from cars that sat for years and any remaining fuel evaporated leaving a residue. So what's the best way of cleaning out the tanks, I was thinking of using a gallon of cheap cellulose thinner to clean the inside of the tanks?

[uwbuurman]

If it is only that, just dry residue, than it might work. If there is some rust, surface of a bit more, I recommend some sharpedged gravel, put it in, plug the holes and start shaking... after clraning the tanks out, I used a piece of gardenhose on the vaccuum, you can do the trick you suggested. Than it is bound to be clean.

[e21Keith]

I can't see any rust but i havent checked all the tanks I have. the inside of the tank looks like its galvanised or something as bare metal would have rusted by now. |don't really want to attack the coating so I'll go with the thinner first.
Many thanks

[uwbuurman]

You can recoat them. But also you can use some cottonballs or marbles wrapped in toiletpaper.