We used to play this game in a dis-used railway tunnel where you stuck lumps of mud or clay on a long stick and then catapulted them through the air at the other team/gang. The mud would go a very long way if you got it just right.
Eventually we got bored of mud and progressed to using old semi-clotted gloss paint from somebody's shed, which was made a much more spectacular impact when you hit something, or someone.
Then we found out that gloss paint is flammable and looks really cool as it goes flying down a railway tunnel in a ball of flames.
What a great game that was! Shame we had to stop playing it after Robert Hendy got accidentally napalmed.