What should I do on the trail when I get mud caked in my chain, derailleur or cassette? I took my new fat bike out for my first mountain ride and immediately got caught in mud. Before I knew it my entire drive train was caked in mud. (me too!) Thick, heavy, clay-like mud. A few minutes later, I was testing out the gears in a parking lot and the next thing I know my chain got stuck and ripped off the rear derailleur. 

I've seen advice on how to clean my bike, how to ride in the mud, what kind of equipment is best for the mud, etc. Of course, avoiding mud for safety and environmental reasons is great advice. What I want to know is "what should I have done differently?" What do you do if you're on a trail and you get mud in your drive train?
Mountain bikes weren't invented last time I had this problem.

Since you're already covered in mud, wipe much of it off with your hands. Be careful to keep fingers out of the parts that bite.

Use a stick where it's dangerous to poke your fingers, and get mud out of the derailleurs.

Depending on the kind of mud, and water availability


dunk the whole bike in a puddle or such.
use your water bottle to hose mud out of the important bits.
urine works too ...