There are a few things you need in order to make cannonballs in Old School RuneScape. The first is a cannonball, which can be found by killing monsters or looting chests. The second is some runes, which you will need to cast the spell “fireball”. The third is an item called a “flammable oil”, which you will need to light the cannonball with. Finally, you will need some water and a bucket to pour it into the cannonball and set it off.
