Last week, Erin covered using Potassium Permanganate to treat drinking water. She also mentioned that it can be used as a disinfectant, which got me curious. So, here's how to get even more mileage from your PotPerm.
In its concentrated form, potassium permanganate is caustic and will burn, so it needs to be diluted. How far you dilute it depends on the use. As Erin pointed out, the lightest pink is safe for ingestion, but nothing past that. Disinfectant levels of potassium permanganate in water occupy the next two levels of color. Also, be advised that PotPerm tends to stain, including skin and any vessel it is used in.
For basic sores from skin irritation (eczema, etc.): A solution of 1:10,000 is recommended, used as a bath. This gives a pink color to the solution, roughly the level used to treat water for drinking (no darker than bottle #2 from the left). Used twice daily for two days, this will relieve sores and soothe pain. This treatment is not recommended for sores from dry skin conditions.
For blisters and other topical sores: Make a 1:1,000 solution (similar to bottle #3), soak rags in it and then cover the area in 20 minute intervals, allowing the area to dry between treatments. This procedure is particularly effective on weeping or draining sores. These sores are gross, and addressing them promptly is important. This is where the real beauty of PotPerm as a disinfectant comes through.
For use as an antifungal: A 1% solution (darker than #3 but not as dark as bottle #4) is recommended. This covers tinea pedis (Athlete's Foot) and similar conditions. Use the same treatment procedure as with eczema.
All treatment methodologies come from DermNetNZ (New Zealand Dermatological Society) and the WHO. The EPA also has an interesting .pdf about potassium permanganate, if that catches your attention.
As such a simple disinfectant and antiseptic, I'll be adding a bottle to each of my car kits. I'm a sucker for multipurpose gear, and this covers such a wide base as to not be missed.