Yes if your duck allows, get it to stand in a epsom salt bath, just his foot, for 20 minutes and then massage and gently squeeze the area to see if you can get anything out. Usually something embedded will work its way out eventually as will the pus with bumblefoot.
I will try to get one by tomorrow.
So just squeeze without making a cut? Okay, thank you. Is it possible that a epsom salt soak would help?