I recently discovered this and figured I would share. One thing that has always been problematic for me after paddling in the surf is dealing with all the wet sand that ends up on my boat between the beach and the car. I am not anal about my boats, but all the wet sand on my boat ends up on the roof of my car after loading it up and generally makes a mess. I have tried bringing portable sprayers and saw horses to clean them up prior to loading, but this has never worked well.
I recently discovered the simplest and most effective solution: a mason brush. You can get one at any hardware store. It brushes wet or dry sand off your boat and paddles completely and works better and faster than even a garden hose. Keeps your gear and your car a lot cleaner and saves the wear on your gelcoat from loading up a sandy boat.