Hi, I’m arranging a waltz and I want to indicate my left hand notes on beats 2 & 3 to be played by the left hand, but they are in the treble clef and might be confused to be played by the right hand. How do I indicate they be played by the left hand?
m.s. (mano sordino) can be written by the notes to indicate they are to be played by the left hand. Or for plebes like me, just write LH! 
Another option: brackets.
Just curious. Why do you want them played by the left hand? The whole treble bar can certainly be managed by the right hand.
Dan, yes it is Italian, though
m.s. is short for “mano sinistra” (left hand)
HA! Oops. “muted hand”… I think it’s past my bedtime…