Hi Debbie,
I've been dealing with a chin with a broken foot this week also. Not only did Louise break her foot in 2 places, but the bone must have broken the skin and she had a nasty infection that swelled her foot to 3 times the size, and it was purple. The vet did not cast the leg so that we could take care of the infection. She also said to try to keep her as immobile as possible - small cage, no wheel or shelves to jump on. Louise was put on antibiotics, but the vet also said that their feet do not get the best circulation so I would have to apply heat to reduce the swelling and help the antibiotics get to the infection. I tried using her method, soaking a washcloth in hot water and applying it to the chin's foot, Louise did not like having a wet foot and the washcloth cooled too quickly, so I did something else. I got a heating pad, turned it up high, put a t-shirt on top of it, and held Louise while she sat on top of the heating pad. She didn't seem to mind it much and I could get her to stay there about 15-20 min. Within 3 days, her foot was back to the normal size, and the dark pink/purple color was gone.. The heating pad really helped with her foot/leg circulation and I would recommend you try it ASAP!
Hope this helps,
Karen