One of my players is trying to create a fist full of sleeping powder as an enchanted item.  Currently, we have it stated as an attack with taken out / consequences just being narrated accordingly.  He will need a skill to target it (blowing it in their face is the described action) so we're leaning toward Stealth (since he's trying to be sneaky about it) but I could also see it being Weapons.  IMO, the damage is against the physical stress track, though the player was pushing for mental. 

How would the rest of you handle this item?

Thanks in advance for any suggestions.