You can get betadine in your local pharmacy. It is iodine, with a brand name.
Allowing her to perch at all is not going to help her foot. As long as her foot is wrapped around something the tendons are going to continue to tighten and take on the shape of whatever it is she's perching on. I'd say a ladder is even worse than a perch because generally the rungs are even smaller in diameter.
Heather brought up a good option, get her a large diameter perch if she HAS to have one because of loose stools, the bigger, the better, you want her toes to be as extended as possible, her foot as flat as you can get it. Allowing her to play on a table or the floor covered with paper towels, newspaper, or the like, for as much time as you can manage everyday would also be very therapeutic.
