Clean is relative.
for me, it's cleaning the barrels with a bronze brush (muzzels down into the waste basket), a plastic solvent soaked patch, a little soaking time, a dry patch, and finished by an oiled patch.
But, I think you mean "What should I wipe my guns down with after I go shooting?"
If that is the case, then I recommend just purchasing a couple tubes, of the oil impregnated wipes (they dispense like a handi-wipe ) and leave them down in the useless cup holders found on the lower section of the doors of most American pickup trucks.
When you return to the truck, prior to casing, just pull one off, and wipe all the metal down.
They don't allow over oiling, and, they leave a nice film that will resist moisture from getting into your slip.
They have saved me from thousands of dollars of refinishing, because I habituated the wiping down upon arrival.
