first you need:
first put some vinegar in the bottle.
then take some baking soda pour it on and fold it into a ball.
then feed it onto your skewer
now screw a hole in your cap with a drill so it looks like this
then feed it through your cap and put it on the bottle like this if you did it right when you step on the skewer it releases the baking soda into the vinegar blowing up the bottle in about 10 seconds.
remember to subscribe if i get 10 subscribers i will make another awesome airsoft grenade.