Each trip the range results in many many many rounds and although cleaning the upper makes perfect sense as malfunctions start to happen the dirtier it gets.

How often should the lower be cleaned?

You can see, the mess in the lower is pretty nasty, but wouldn't think stripping the lower after each trip to the range would be a good idea. And attempting to clean the lower with all the parts in tacked is a waste of time.

What is the rule for when to strip the lower for cleaning?

I clean my lower receivers each time I fire the rifles. The lower is just as critical as the rest of the weapon. There’s no need to completely strip the lower of it’s internal parts, just flush it out with solvent then blow dry with compressed air and re-lube.

        Not every time, (and I will never strip unless I am swapping triggers) I keep one lower that is used with the Ceiner and the Oly 9mm,both are of course blowback and puke all kinds of junk down into the trigger. This lower gets cleaned more oftem than all the others but since it is just a toy I will sometimes let it slide.Most of my other shooting is only range use and the lower stays fairly clean.
         Solvent or brake cleaner ,blow dry,and relube seems the way to go to me,driveing the pins in and out (I use the RRNM with the oversize pins,I polish them down so they are slightly less tight,but still tighter than factory) would seem to cause more wear than any small bit of crud that the solvent and compressed air misses.

I like that paint brush idea and will have to give that a try.

Quoted: I like that paint brush idea and will have to give that a try.

I recently had a lengthy discussion over my AR cleaning and maintenance procedures, which happen to be pet peeves of mine!

Many people think this procedure is over kill but in actuality it’s easier than trying to monkey f*ck around with q-tips digging around in my lower receiver leaving a bunch of cotton fuzz behind! It’s quick, effective and leaves me more time to concentrate on other areas of the weapon.

For solvent you can use turpentine or mineral spirits. I mix mine with a little Hoppes #9 to help cut through any carbon that might be present. Don’t toss the mixture when your done. Store it in a glass jar. When it’s time to use it again the grime will have settled to the bottom of the jar leaving clean solvent on top you can pour off!

A cheap paint brush aids in cleaning, and your wifes turkey baster works great for flushing things out!