That happened to my poor baby and i started off doing the exact thing as you are doing with the soaking and wrap it up if your duck is going outside. I never squeezed anything out of it or anything because she was in pain. Another thing i did was i injected cleocin (clindamycin) right into the spot and she ended up healing quicker than i thought she would. You will have to talk to your vet to see if they will give you that antibiotic.
We made an appointment with the closest exotics/avian vet. Unfortunately since she's the closest, she has lots of patients and can't see us until next week. Unfortunately I don't have time or money to be able to go in as an emergency. In the meantime we'll be soaking and vetericyn-ing her foot. She is eating and drinking water though, pooping normal. So at least it hasn't gotten tooooooo too serious. I hope it stays that way!
Glad you can take her in. Call them back and ask them to call you if they have any cancellations.
-Kathy