I have some ideas but not sure if they would be legal. A pump used in construction to remove water that runs on gas and a 2” or so hose that comes off of it. You’re going to get in the water with it and use it to wash the mud out of where it is to where you want it.
Another is to tie off to both rear cleats to the corners of your slip with the prop wash going into the slip, pushing the water into the slip and displacing whatever is in the slip.
These are just ideas but maybe they’ll start the juices flowing.
Creativity is just intelligence fooling around