Before you use a solvent, make sure it's safe for the purpose and isn't going to damage your gun. These substances are typically flammable. If used for the wrong purpose they can combust or cause an explosion. Common uses and potential issues are described below.

 GUN BORE CLEANER :  Standard bore cleaners are used for steel barrels. A bore brush can be dampened with cleaner to help remove rust and fouling. Patches or cleaning pellets lightly dampened with cleaner should be pushed or pulled through in the direction ammo travels. Dry ones should be used to remove remaining solvent. A light coat of oil should be applied after cleaning to inhibit corrosion and fouling. Some should be left dry after cleaning, this generally pertains to high-precision firearm barrels. In those no oil should be used after cleaning until the barrel is thoroughly broken-in, then dry patches should be used after oiling so very little residual oil is left. Bore cleaner is corrosive to brass barrels and other parts made from, or plated with, soft metals. Brass barrels should be cleaned with oil only and metal brushes should never be used. Bore cleaners are flammable, make sure they don't get into parts that will be exposed to high pressure other than the barrel.

 PENETRATING OILS :  WD-40, Liquid Wrench and similar petroleum solvents are highly flammable. These should not be used to lubricate any part of an airgun, tank, pump or introduced into any pressurized component. Doing so could cause an explosion.

ACETONE :  Commonly used to clean metal parts for touch-ups and refinishing. It will dissolve many plastic parts, paints and coatings. This includes grips, forearms and some of the markings on sights. Acetone is flammable and the fumes are explosive.

 ISOPROPYL ALCOHOL :  Commonly used to clean parts, removes oil and grease. It won't dissolve plastic or paint. It's flammable and can produce explosive vapors in a small enclosed space.

 DISH SOAP :  This is an excellent parts cleaner that dissolves oil and grease. It can be used undiluted or mixed with varying amounts of water and easily rinses clean. Steel parts should be dried immediately and oiled to prevent corrosion.