Cleaning Gas Tanks

[PeaceRiverRider]

I recently acquired two tempo portable plastic gas tanks which had been sitting for a few years. There is some residue at the bottom. I put some "Dawn" detergent and water in them and will let them soak for a few days out in the sun.

If for some reason this doesn't work does anyone have any recommendations on how to clean them?

[GregF]

The welder I used to fix my old Jeep gas tank says ammonia and steam is the only thing he trusts.
He had a deal with a local car wash that steam cleaned mats.

[dockholiday]

might add some ammonia to the mix you have.

[pontchartraintoon]

Last year, I removed my tank, and was amazed at the solidified crap at the bottom. I put a good dose of the Purple Cleaner from Walmart in there and it took everything away. I actually use it to clean my carbs too. It disolves everything. Just keep an eye on them as it doesn't take long to score the aluminum.

[PeaceRiverRider]

UPDATE:

One of the tanks was easy. I let the other tank sit in the hot Florida sun with the dawn and ammonia mixture for weeks. Helped some but there was still some stuff in there. I ended up boiling some water and pouring it in. That did the trick.

[Paublo]

If you have some residue that doesn't want to come off, dump a handfull of old screws into the tank too. Shake it hard and they will break it loose. I have used a little solvent and that seems quicker and more effective than a detergent based product.

[GregF]

I agree on the solvent. Mineral spirits or lacquer thinner spring to mind.