I had some left over kimchi and my parrot jumped into it. I used sink water to clean his legs and I used wet tissue to try to get as much of it out of his feathers. But it's still a little bit stained and he still sort of smells like kimchi.
At least it's not toxic stuff!
Yeah, lots of water water water water...
I know Dawn detergent is used to get oil off wild birds... maybe a dilute mixture of that?
The Rbird jumped into a sink of soapy water once... can't recall the brand, but he was fine after getting rinsed.
As already suggested a good soaking bath/shower with clean plain water will probably do the trick. Sooner rather later just in case of any irritation to his skin.
If his feathers are covered it may start off some over preening of his feathers which is best avoided. Not a habit to encourage IMO.