Don't go there

So my office shares the floor bathroom with another downright ghetto company. They have a revoloving door of personnel, so needless to say, they have no respect for the bathroom. It is not uncommon to walk in and find wads of paper towels or toilet paper scattered on the floor. Sometimes I like to amuse myself by playing the "which stall is clogged up" game. Well today I found in my stall a VIAL OF BLOOD! Yes, you read correctly. Seriously, why the hell would you have a vial of blood with you, let a lone put it on the toilet tank? It makes me glad that I pulled the hover maneuver because the previous occupant obviously has something. I'm posed with the conundrum, do I post a "lost and found" sign in the bathroom (you know, 'FOUND, VIAL OF BLOOD') or wait till the owner realizes they have left a test tube filled with their blood in the ladies room.