Wet tumbling brass is THE way to go.
It cleans the inside of the cases as well as the outside. Brass can come out looking almost brand new.
And it's not expensive.
A tumbler designed for wet tumbling. Stainless pins, water & LemiShine. I don't use dish detergent because of the suds & amount of rinsing I have to do.
Yes,, the pins are totally reusable.
I use a pair of Dillon media separators to remove the pins. Both have clean water in the catch tub. I first pour off the dirty water as much as possible, w/o spilling any brass or pins. Then, I dump my pins & brass in the separator, close it, set it in the tub with about 1"-1-1/2" of water in the bottom of the separator. I gently rotate it,, allowing the pins to fall through the separator, into the bottom of the tub. Once I feel I've gotten all the pins out of the brass,, I switch tubs,, and rinse a second time in cleaner water.
I then shake off as much water as possible,, before putting the brass into a dehydrator. You can skip this step,, and just place the brass on a towel, and allow it to air dry. If you do this,, occasionally shift the brass to a clean & dryer towel. The towel of brass can be placed in the sun, or near a heater.
Clean brass doesn't have the chance to scar or damage my dies.