I don't sonic clean, but have had to wash some dirty cases. Depending on how many I have put in a warm oven before or if there are not many have put a rubber band around them and... don't tell anyone... used my wife's hair dryer.
Get the standing water out of them and roll them a bit in a towel. Done.
chance of moister in brass is not a good thing
Maybe I should have been more complete in my directions......
Lay down a towel. Take each piece of brass and briskly tap it upside down several times on said towel. Then put brass in a pile on towel and pull towel ends together. Shake towel like crazy for about a minute. If brass is still showing a bit of moisture repeat towel shake. Let brass dry on another clean towel for 24-48 hours.
. There's a fine line between BRAVE ... and STUPID.