Before he died, Dick Trenk, who was Competition Events Director for Pedersoli, wrote a short article titled "Charging Cases for Best Accuracy". In that article, he wrote, in part: "This charge is then poured into the case via a drop tube or as I am currently doing, dumped into the case fast and the cases are vibrated on a home made (electric razor) device for 25 seconds."
Searches here have been less than successful for me, so I will just ask everyone: Show me your home made case vibration devices.