i clean mine preeeeeety frequently....im particular about my guns.....i like to start with the bore brush...with my gun oil on it.....being i dont fire mass quantities of ammo for the most past......everything comes up fairly easily....and the oil loosens it and lubes the brush.....then a few dry patches...a oil patch.....and dry patches till they are clean....then if its being stored ill run one lightly oiled patch through it....your guns may need solvent.....probably a good copper solvent would be your best bet since thats most of the fouling from a smokeless cartridge....someone should recomend something better.....good luck....it should all come out with a little work and a good solvent...but i dont use solvents much at all so i cant help there