why dust is used for money or cash in the American slang? [closed]
I honestly have never run into this as slang for money in written or spoken word. As others have mentioned it appears it could be an old gold mining slang word since you could pay for goods and services (mostly alcohol and prostitutes); of course much of my knowledge on the time period comes from Deadwood.
What I have heard and marketplace.org has confirmed is that dust can refer to a lack of money.
Example:
Dust -- As in "nothing but."
Person A: "Let me borrow 5 bucks."
Person B: "I got dust."