Replying to I need ur help ns. need to get back coworkers

So I bring a gallon of milk to work and leave it in the fridge. At my work there are two shifts, the morning shift and night shift, i work the morning shift. So when I'm not there during the night shift, i can tell someone has been drinking my milk. I've caught on to this the past week, noticing little by little that its been getting used. I want to put something in it that can't be detected easily by smell or sight. i was thinking exlax or some chlorine or something. I really want to get those Fuckin dirty Mexicans back. I want something that will seriously fuck them up like some acid or some shit. Please NS give me some ideas I need to get back thise fuckin bitches.