No worries..I actually made these with easy use in mind.

[With that he pulled out one of the glass vials and explained to her the parts-- the stopper that he had secured onto the tube to plug it shut and the thin dividing seal between the two liquid suspensions within. A twist of the stopper and a sharp shake, as he demonstrated, was enough to get the chemical reaction within started.]

It's a little bit of basic chemistry combined with a little blood magic, [he explained.] You should be fine if it breaks, just wash off your hands afterwards and make sure none of it gets in your eyes or mouth.

There's a cleaning solution in there. It will hurt if you do.