We anchor in clay or sandy-clay most of the time. We've had washdown systems on our last two boats. The Groco washdown kit (which isn't inexpensive) is by far the best compared with similar, lest robust, plastic pump systems (e.g., Shurflo). More volume, more pressure, etc.

Depending on how your "leave" your anchorage (ie., Are you in rush? Are you willing to lift slowly and let the debris "wash-off" more naturally from the up- and down- motions? Are you willing to motor slowly and clean the flukes? etc.)

Sand is obviously more foregiving than clay or "Mud".