Any swelling to the feet or wound can be benefited by a soak with the epsom salts...it's takes the throb and pain out of it. The castor oil is a natural antibacterial, antimicrobial, antifungal, and even a natural insecticide...but it's also a great anti-inflammatory and will take the pain out of the site as well. Castor oil is also known for helping to regrow skin and hair quickly, so it covers all the bases when it comes to wounds or damaged scales due to scale mite.
This is the 2nd time today I've read about the benefits of castor oil. Someone on another thread was discussing how it helped them with their knee pain (for themselves, not their birds).
Interesting stuff!