Locker and crate smokes/foams

[Frank_Stein]

Why not add a reagent that is sensitive to light? Being in lockers inside of brightly lit rooms doesn't set it off, neither does being in a dimly lit room.

That could be a really fun reagent. I just imagine some guy mixing stuff in a dark room and having someone come in, turn the lights on, and burn the whole place down.

Carrying it around in a bag or box should keep it from reacting. Maybe some opaque beakers could be added as well?