Funilly enough I only ever used Sea clean in mine until I read this, tried a squirt of fairy liquid and it made a hell of a difference.
I tend to just rinse them in as hot a water as I can then shake them out and leave them on a towel to dry or bung them in an old sock and leave them on the rad. I am lucky as I can came as much mess as I like in the utility room
The only slight niggle is that the STM will peen the case mouth edge a bit, but I run all cases through a 3in1 cutter after each sizing anyway. We cycle pretty quickly so the nice shiny cases help avoid poor feeds...hopefully
I would not use anything else now