The sandwiches you take to work are also known as "chits". I think this is short for chittering piece and was originally a piece your mother gave you when you were shivering eg when you came out of the baths. Can anyone confirm this? Another example of rhyming slang was "coral diver" for a fiver, and at the risk of lowering the tone of this discussion young men used to go to the dancing intent on getting their Nat King unless of course you were a horses hoof. I am sure only Glasgow delicacy has prevented previous contributors from alluding to these very common usages.