I almost went past this one.....
If I told you I have cases I have fired 40 times without cleaning...... you'd probably think I was lying..... and I'm sure with good reason. But fact is,I shoot a low pressure load of Blue Dot or milsurp#107 in my 44 Mag and have cases that have been fired 40 and possibly more times and not ever cleaned. And the load is DIRTY I mean so dirty that it will get so bad the gun won't lock up. (takes about 250 rounds)
I only size the case about 3/8" of the neck and of course am using a carbide die. I have 357 Maximum cases, sized in like manner and used only in mild loads with similar mileage and never cleaned.
To put that in perspective, I neck size my 30-30 brass with a Lee Collet die, and dont clean it either, but I run it hot enough that it don't get all sooty either, so far the brass fails before I have a failure that I can say was because of dirty brass.
Some folks say that any dirt or soot is hard on a die. Just how hard is this soot? Ever try to stamp a die with lettering? Dies are HARD. Probably take 100,000 ore more sizings to wear one to replacement. Now you might get some silica between your brass and your die and that might scratch it, but I bet the brass scratches first. Besides, when was the last time you sized cases that were covered in sand?
If you are full length sizing and using loads anywhere close to maximum pressures, your brass will fail from work hardening before it needs cleaned. I know that goes against the grain of conventional practice, but most reloaders I know are anal retentive types (me included) who are into excessivly greater amounts of perfection for exceeding smaller returns.
I had a heart attack 4 years 3 months ago now and today I do more and more questioning of just how much nitpicky stress inducing anal retentive behavior I want in my life. In fact, something falling into one of those catagories is a sure fire way to find me NOT doing it. Someday I might get a tumbler again, it won't be because I think I need shiny brass. It'll be because shiny brass induces a pleasure I enjoy. At present, the only friends I got are ya'll so it ain;t like I need to do this to impress anyone with my kutzpah.
Dirt simple way to clean your brass is to use Lee's case resizing lube. Put a little dab on your finger and rub the case and size it. A pinky finger nail size dollop will lube 30 cases with left overs. When you clean off the lube with a wet rag you will have nice clean cases. This is how my 45-70 cases get cleaned, an unintentioned result from a nessicary action, kinda like 2 for the price of 1. Now that's stress reducing.