The Murray is sohv155 204502a the connecting rod from piston to crank shaft broke and some aluminum is on the crankshaft from the connecting rod
How do I clean off the aluminum without damaging the crank shaft

Sorry to say... if there is aluminum stuck on the crank... its gauled and already damaged due to lack of oil.

Thank you a Google search digested lye baking soda solution
Then vinegar to neutralize it
Would that work or make matters worse

Thank you a google search digested lye baking soda solution
Then vinegar to neutralize it
Would that work or make matters worse

Worth a try... you can't use it as it is now... if you are lucky the Iron crank won't be damaged under it (like as in scored, etc)... but the odds aren't in your favor.

Careful with that stuff... use eye protection and gloves... Lye will melt your skin.