Page 47 - British Museum: SYTYGIB Medieval Castle

It’s often said that they used boiling oil or fat, but that was too expensive. Why waste good boiling fat when you could use cheap hot sand and save the boiling fat for all those things you use boiling fat for? Like, errrr . . . we’ll get back to you on that.
If the straightforward route failed, something bigger was required.
Men in the invading army called sappers would dig tunnels and when they were under the castle walls, they’d set fire to the wooden supports holding up the roof, and CrAsH! The tunnel, and the walls above, would come tumbling down.
FANCY THAT!
One of the smelliest jobs, apart from the gong farmer, was a tanner, who prepared animal skins for use. Once the hair was removed, the tanners would soften the material by pounding dung into the skin. Dog and pigeon poop were commonly used. Put it this way, you wouldn’t want to be stuck in a lift with a tanner after a hard shift.
Catapults and other huge weapons were also used to hurl boulders at the walls to try to destroy them. Sometimes catapults went wrong, which could have grim results. Knights and men could
be crushed by boulders from their own weapons if they broke and only threw their projectiles a short distance. A suit of armour wasn’t much protection from a rock the size of a car!
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Battles and Sieges