I let it soaked in 50/50 water and windex mix if shooting BP.
If your using bh209 you'll need to hand spin a drill bit
T/C, Traditions. CVA using the Blackhorn breech plug and most Knight breech plugs use a 1/8″ drill bit
For the CVA non-quick release breech plug (REQUIRING A TOOL TO REMOVE) use a #32 drill bit. Numbered drill bits are machinist bits and can be found at various online supply houses like ENCO, or search “numbered drill bits” for more