Sig Sauer pistols are quality firearms requiring routine maintenance. Cleaning your gun should be a ritual after shooting activities and extended periods without use.
Always physically and visually verify a gun is completely unloaded before you begin cleaning.
Sigs are expensive guns, and routine cleaning should assure a lifetime of service. As with most firearms, disassembly is required to adequately clean your pistol. Basic instructions should be detailed in your owner's manual. Downloads of most Sig manuals are available on the company's website. Cleaning should involve brushing and wiping carbon residue from the internal surfaces of the slide. Plastic brushes and lint-free cloth, such as a cotton diaper, will suffice. Internal parts of the frame should be wiped down but not lubricated. Push a rag through the magazine well using the brush or cleaning rod. Some shooters prefer to use cleaning solvent and lubricant on the barrel in multiple steps. If using a solvent, be very aware of how corrosive the particular product you're using is. Some solvents will corrode the metal rapidly if you have to stop in the middle of cleaning and don't get back to it for awhile. With other solvents, you can soak parts in them for hours or even days with no destructive effects. Cleaning the barrel should be done in repeated steps depending on how dirty it is. A copper brush can be used to knock out loose particles. Then run wet patches through, pausing for brief periods to allow the solvent to soak in. Dry patch the barrel and then repeat these steps until the patches come out clean. When the barrel is clean, push a wet patch through with a lubricant. Again, let it soak into the metal. Dry patch until the patch comes out dry. The metal soaks up what it needs, so no lubricant should be evident on the final patch. Some shooters use only a single product throughout the cleaning process, such as a Cleaner, Lubricant Protectant. A good CLP will suffice to get the job done, start to finish. As the barrel soaks between patches, brush and wipe the gun down. Sig recommends paying special attention to cleaning the extractor and verifying the extractor spring is functioning properly, as extensive shooting can cause carbon buildup in the crannies surrounding the assembly. A solvent may be required if residue is packed in too tightly. Also clean the firing pin hole inside the breech.
Assembly should be the reverse of the disassemby process. When the gun is back together, wipe down the exterior. A lubricant can be applied to treat the metal, but wipe it thoroughly, removing all surface fluid before storage. A simple function test should be conducted before the gun is used again.