Step 1: Equipment
1 Film canister or air tight container with a pop open lid.
1 Cardboard sheet (thin- Cereal box type)
1 Plastic sandwich bag
Some Bicarbonate of Soda (or Baking Soda)
Some Powder- flour, pepper, allspice....
Some Celotape or sticky tape
1 pair of scissors
1 Bomb site
Step 2: Cutting
2. Hold the corner of the plastic bag against the canister(so that the corner is pointing straight down) and cut just below the top of the canister to form a cone.(Thank you James M)
3. Cut some string (or any material like it) that is about 10cm or 4 inches long then take the celotape and stick one end of the string to the canister and one end to the lid leaving a bit of slack in the middle so that the top can blow off.
Step 3: Construction
ALTHOUGH AS I TOOK THIS PICTURE, THAT MOST EVIL OF THINGS THE WASP ATTACKED ME AND MADE ME SPILL VINEGAR ON MY HAND!!!!!
Step 4: The Grenade
Step 5: The Powder
Then take the powder and pour it on to the top of the cardboard up until it reaches the top of the canister then carefully put the lid on making sure that the grenade is always up right until throwing.