I started out many years ago using Vinegar with water, but through reading it seems Vinegar attacks the brass in a way that's not good, I think it make it brittle too.
I notice that brass I cleaned years ago with vinegar have all turned a dark amber color, as it keeps oxidizing the brass.
The active ingredient in Hornady One Shot, and others, is Citric Acid. And after I started using that, I notice the brass is clean and does not oxidize like the vinegar. I use about a teaspoon of powdered citric acid with about 40 ounces of regular water. You can add a few drops of Dawn to it to help clean also.
A good source for citric acid powder is brew supply places, it's used in making wine. It's pretty cheap. I bought a pound of it and put it in an empty peanut butter container, marked it with a label.
The cleaning solution works better when its hot. I have a larger empty juice container, and I marked a line on it for 40 and 60 ounces. 40 ounce for a smaller batch I use 1 tps of citric acid, or a larger batch 60 ounces use 1.5 tps citric acid. 60 ounces mostly fills my Harbor Freight ultrasonic cleaner.
I start to fill the the juice container with hot tap water, and part way through stop and add the citric acid powder, then fill the remainder. Then I can agitate the container and dissolve the powder in the water.
When I pour the mixed solution into the ultrasonic cleaner bin, I stop about 2/3 way through and add a few drops of Dawn liquid (so it doesn't foam up too much) and gently add the rest of the solution, to help evenly disburse the soap.
After I clean the brass I put it into a bowl with running hot water, to rinse the cleaning solution from inside and outside the brass, before I dry it. Neutralize the acidity, also can add a little baking soda.
You can use the juice container to store the mixed solution, if you did not use it much. And remember, before you start to clean shot brass that's been on the ground, to rinse it in a colander with a little soap, to get the loose dirt off, makes the solution last a lot longer as it stays clean. (ask me how I know).