2nd GBExpat
Auto wash and wax (tumbler gets what the car gets, car gets what's on sale, usually seems to be Turtle)+Citric acid from the canning section of your supermarket.
(used a couple flavors of wash and wax, all seem about the same on cases, the more expensive stuff works better on the car
)
This is enough citric acid to do LOTS of cases
https://www.amazon.com/Milliard-Citric-Acid-Pound-VERIFIED/dp/B00EYFKNL8/ref=sr_1_5?crid=1PZDG2V7F7FWR&dchild=1&keywords=citric+acid&qid=1605484672&sprefix=citric,aps,231&sr=8-5
5lbs $15...
About a 9mm to 45 case full of acid, depends on your water PH and a splash of wash and wax (couple oz)
Wash and wax amount is not critical, to much acid is bad.
Edit: My water is high PH so I need more acid than most...for most people probably more like 1/2 a 9mm case
Do not use paste or liquid car wax, just the wash and wax.
(I know do not use paste wax from trying it, major mess, everything covered with grey slime...)
Wash and wax helps prevent tarnish, makes sizing easier.
Wondering about spending the money for a wet tumbler (got a Lyman Cyclone) was sure happy after I did after the first batch.
Shiny brass may not shoot any better but it makes me smile, and after seeing the crud that's in the water it's nice to not have it in my dies or on my fingers.
Please let us know how you like it.