Does the brass get dirty enough to require some cleaning?
The brass does get somewhat dirty after firing, I threw mine in a tumbler just to make them all nice and shiny, but most have tarnished somewhat anyway.
The brass does not expand when fired so removal from the breech plug is very easy. There is no need to resize the brass either, as a result the brass can be used over and over again. Just pop out the old primer and put in a new one.
When I first got my Omega converted I went on a .25 ACP casing scrounging bin, I now have over 1,000 pieces of brass and 500 are primed and ready to go. I doubt if I will ever need any more .25 ACP brass…