A motorcycle's plastic gas tank is porous. This means that gas can seep through from the tank to the outer plastic, leaving ugly stains behind. A gas stain is easy to identify by its yellow colour. To prevent stains, drain the gas tank periodically and clean the outside of the tank regularly. Wash the tank with a cleaner that contains a mild abrasive. Applying wax to the plastic helps reduce staining by sealing the pores in the plastic.
Wet the gas stain with water. When using a cleaning product that contains an abrasive, applying it to dry plastic can lead to scratching.
Wet the wash cloth and wring out any excess moisture. Apply the cleaner directly to the wet wash cloth. Cleaners that contain an abrasive come in both liquid and powdered forms. Both mediums work equally well.
Rub the cleaner over the gas stain. Use a quick, circular motion with medium pressure. When cleaning with an abrasive, using firm pressure can lead to the plastic becoming scratched.
Continue to rub until the gas stain is gone. If the stain is proving difficult to remove, apply a small amount of cleaner directly to the stain and leave for up to one hour.
Rinse away the cleaner and towel dry the plastic. Wax the motorcycle when done. Waxing helps seal the pores in the plastic, making staining more difficult.