clean up/clean out/clean off

clean up=clean out
 "Clean up" is certainly used to refer to stains. "Clean off" certainly refers to clearing things away, as from a table, etc. "Clean up" also refers to cleaning up rooms, language, behavior etc. "Clean off" generally refers to physical things. Here are some examples:

Johnny, clean up your room! It's really messy in here.
You'd better clean up your act. You've been drinking too much lately.
I'll have to clean up my language if I want to impress her.
I cleaned off the wall that had been spattered with blood.
I cleaned the blood off the wall.