Guns can be very expensive, especially chrome ones. Chrome is an expensive, high-quality, stainless brand of silver. Even though it's meant to be stainless, it can sometimes tarnish much like silver will. Needless to say, if the gun is stored in a dusty place or is handled a lot, it will eventually need to be cleaned. Cleaning a gun is, for the most part, a simple procedure.
Take the vinegar or baking soda and make up a mixture of 2 parts of water to 1 part of the cleaning agent. You'll need vinegar or baking soda. Vinegar cleans better, but baking soda is less harsh on the chrome. So it really depends on how bad your gun is tarnished.
Dip your sponge into the mixture and begin polishing the tarnished part of the gun. If you're simply wiping the gun off to get it free of fingerprints or dust, just wipe in a regular motion until the dirt and grime is gone. Make sure not to touch it after that if you can avoid it so as to not put more fingerprints on the part you just cleaned.
Scrub lightly the tarnished area until the dirty spot comes off. If it doesn't come off, apply some of the mixture on top of the stain and let it sit for an hour or so. Check up on it every few minutes to make sure it's not damaging your gun further.
Clean your gun further with a gun cleaning kit or gun polish. This is what is used most often to clean semi-automatic or handguns. In the cleaning kit there should be a cleaning agent that is safe to spray inside the barrel of the gun. If there is not, purchase this product. Spray inside the barrel of the gun and let it sit.
Wipe off your gun with your second sponge. This will wipe all the excess cleaning solvent off the gun to ensure maximum shine and clean. Make sure all the dirt is off the gun, if you plan on using the gun anytime soon.