Easiest Way to Clean a Gasoline Tankby Kate Carpenter
When a gasoline tank for a motor has not been utilized in a long time, there is a good possibility the tank needs to be cleaned. Old gasoline, rust or sludge that is in the tank can clog and cause significant problems for the engine if it is not cleaned out of the tank.
Unfortunately, the only effective way to clean a gasoline tank of sludge, grunge and rust is to first remove it. Then, because often there is a gallon or two of old gas at the bottom, empty out of the old gasoline from the tank. To remove as much of the greasy substance in the tank, pour a gallon or two of acetone into the tank and slosh it around vigorously. It helps if you have one or two friends to help you with this, or suspend the tank using heavy duty bungee cords that allow you to turn and shake the tank. Drain the tank of the gasoline and loosened sludge. You may need to do this more than once if the sludge is thick and gummy.
To remove any remaining sludge and rust, put 6 to 12 good size nuts and bolts, marbles, a piece of heavy chain or rocks into the tank. Add two or three gallons of gasoline, kerosene or water. If your gas cap has a floater attached, do not put the cap on but instead put duck tape over the opening. Again slosh this mixture around vigorously. The easiest way to get the best sloshing is to place and secure the tank in the back of your pick up and drive over bumpy roads for a day or two. Or use the suspended method in Step One. Once you have done this, again, drain the tank of the liquid and bolts, nuts, rocks or marbles. When you use nuts and bolts, you will see a lot of gunk attached to them. If you still see loose sludge or rust inside the tank, take it to a car wash and pressure wash the inside. Make sure you thoroughly rinse the tank and allow several days to dry out any water droplets that may still be inside or use a hand held hair dryer inserted into the opening to help speed the drying process. Finally, rinse the tank with a gallon of fresh gasoline and repeat this step until the gasoline comes out clean. If your tank did not have any sludge in it but only rust, you can use this method without any gasoline, kerosene or water added to the nuts and bolts, rocks, marbles or chains. It is still a good idea to rinse your tank with fresh gasoline afterward to remove any rust dust and small rust particles.