There are four handguns that more or less live in my range bag: My Ruger MkIII 22/45 and my Para LTC9, which serve as understudies for my CCW 1911s, and my K-22 Target Masterpiece and a 2" Model 64 (stainless .38 Special K-frame, for those who don't speak S&W) that are my revolver trainers.
And when I say "live in my range bag", I mean that they come out to get shot at the range, and then sit in there until the next range trip. (Well, the K-22 usually gets wiped down with oil every couple weeks in deference to its age and blued finish.)
Every three or four months, though, I get to feeling guilty and pull them out to be stripped and cleaned. This means that they are filthy: The Para going sometimes 600 rounds between cleanings, and the 22/45 as much as 3,000 or more.
With the Para and the revolvers, it's not too bad, but the 22/45 is a blowback-operated rimfire, and the action gets an amazing amount of gunk vented back into it over that time. Today it is time to attack the built-up cack in the interior of the Ruger. Perhaps with an air chisel.