Just found what seems to be an opened, very small glass vial containing a drop of clear liquid. It was on the floor in the kitchen and I stood on it. I can't think of what it can be and so am thinking the worst. DS is a student and back home for a few days and had a couple of friends round when I was out. I know that he vapes and smokes weed but wondering if this is something else. Does anyone have any ideas?