The first thing I would do after removal from whats left of the plane is hold the engine under running water to flush all the mud I could from the engine that has already been under water. At that point more water is not going to hurt anything. Then I would disassemble the engine to clean the parts. Even better is to send the parts through an ultrasonic detergent water bath before blowing them dry and oiling them with afterrun oil. At this point you can usually see if you have any damaged parts before re assembly.