Well if it fits in with how every other thread on here ends up it will have do with unpaid rent.
To "Scratch" as if to try and "Scrape" together funds.
To "Scratch" as if to try and remove an annoying itch, like an unpaid bill.
Or to go back to "Scratch" and start again with a clean sheet when nothing is owing.
"Shed" as owing a "Shed Load" of something, such as money.
Or "To Shed" as if to remove something like an unpaid bill.
Hope that clears it up.