i just got a plane from my cousin. Its in pretty old shape. It has burnt oil all over the engine and the muffler and the rudder servo wont move to another side and the little horizontal wing on the back(elevator) is broken. My questions are: What should i use to clean the engine(i cannot take it out)? How do i take out a stripped screw? Anything else i should check for before i start the engine? it hasn't been flown for about 3-4 months. BTW its a Trainer with OS46