LiveLife
Member
I would be concerned that steel is harder than brass for "violent sloshing". I use this one and seen it in action - https://www.homedepot.com/p/Husky-5-gal-Metal-Spiral-Mixer-SM5-HKY/206509458those steel stirrers you put on a 1/2" drill for mixing small batches of concrete ... some pretty violent sloshing around, but shouldn't crush brass if not overly full.
They do make non-metal paint stirrer - https://www.homedepot.com/p/Unbranded-5-Gal-Helix-Paint-Mixer-410-179-0111/309896468
Personally, tossing the 5 gallon bucket in the back of the truck for a spirited drive or rolling around on the lawn would be enough to agitate and loosen dirt.