i would not put DMSO on a duck's foot. It is a carrying agent, and it will carry anything it is put with under the skin.
A duck's foot is in muck and duck poop because that is the way that ducks are. I would not want muck or poop germs carried into the foot.
A duck's foot is in muck and duck poop because that is the way that ducks are. I would not want muck or poop germs carried into the foot.