As the title says, this thread documents a How-To (and Why-To) clean spent cases prior to reloading using Ultrasonic Cleaning System. For this exercise, approximately 3,300 spent 9mm casings were accumulated, prepped, and cleaned using a Chicago Electric Ultrasonic Cleaner available from Harbor Freight Tools, using Hornady's Ultrasonic Case Cleaning Solution. This cleaner was selected because it is the one most likely to be purchased by reloaders (for cost considerations). Time spent for cleaning was a total of two (2) days, following the procedure described in this thread. Photos below are the raw brass from the range.