this was not my idea, i found it on youtube.
WARNING: while using a Flash Grenade, it is a very good idea to wear non-flammable gloves, and sunglasses.
DISCLAIMER: If you end up hurting yourself or others or setting something on fire, then I take no responsibility for it.
Step 1: Materials
Two cigarette lighters, (a small bic one is fine)
the other one is to heat the flint up.