Nothing
Wash your hands with soap and water. This will NOT remove microscopic traces of gun powder residue that can be found with laboratory examination.
If you're talking about a "bubble gun" - the white residue is soap. If you're talking about bubble GUM - it is powdered sugar.
Most of the residue will actually be on your wrist, but yes. After firing any handgun that discharges gunpowder, some of that powder will exit through the gun's chamber and get on your hand/s, wrist, and lower arm.
Black Powder.
The coroner found traces of poison in her system.A police officer observed traces of gun powder residue on Ms. Mason's hands.
Gun powder is always a mixture.
Gun Shot Residue
gun powder was udes for fireworks, then weapons
No. Gunpowder (smokeless powder) has a different composition than dynamite. BOTH may contain some nitroglycerin, but there the formulas take different paths. However, there IS scientific testing for explosives residue as well as for gunshot residue. Since I work with explosives, this makes air travel and security screening an interesting event for me.
Gun Powder is the most important thing in a war because if you don't have gun powder you wouldn't stand a chance.
Up to six months on clothing, even if you try to wash it off it will stay a long time. And on hands its only around a week.