Cleaning the SR-556 is not much different than any other AR pattern rifle. To remove the gas regulator, push the cam pin from left to right until the detent stops any additional travel. Remove the regulator, regulator detent, and piston by rotating the regulator until the flat lines up with the hook on the gas block. Ruger recommends using a brass brush to clean the piston bore in the gas block. They also recommend cleaning the top of the barrel below the vent in the bottom of the gas block with powder solvent and a toothbrush. The piston and the regulator can also be scrubbed with a powder solvent and toothbrush.