If we are not speaking of metaphors...
When a gun is fired, unburned combustion products accumulate in the barrel, along with small amounts of metal from the bullet.
A gun barrel needs to be cleaned after firing to prevent these from fouling the barrel rifling or blocking the chambering or firing of rounds.
In a revolver, the cylinder also needs cleaning to remove these products.
In the old days prior to smokeless powder and non-corrosive primers, the combustion products from ammunition were quite acidic and could cause a steel barrel to rust away from the inside.
The oil in guns also oxidizes over time into a sticky varnish and accumulates dust and dirt, requiring less frequent cleaning of the trigger and other moving parts.
Unloaded
Gun cleaning kits can be purchased online at Amazon, Walmart, and Optics Planet. The price of gun cleaning kits ranges from thirty dollars to over 100 dollars.
unloaded.
Kerosene, Alcohol, pear oil (Amyl Acetate), and ammonia are the main ingredients which are best for gun cleaning purposes.
Goes on the end of a cleaning rod and holds a patch.
NO! CLP, yes. CLR is a strong acid that is meant for cleaning toilets and sinks. It will corrode a gun.
Dishwasher
A gun cleaning kit can be purchased from any sportsman related retail outlets that sells firearms and firearm accessories. Retail outlets such as Cabela's, Gander Mountain, and Dick's Sporting Goods sell gun cleaning kits.
Cleaning a Tokarev gun is simple. All you have to do is have the cleaning supplies and take it apart.
Unloaded
unloaded and depending on how thorough you are it might also be stripped down.
The first step is to very carefully check that the gun is unloaded.