What is the best way to completely remove Mange?

Borax and peroxide is NOT a good solution for mange and can seriously irritate and damage your dogs' skin and worsen the problem. Why would you think that applying a caustic solution to a living animal was a good idea? The dogs need to be taken to the VET for appropriate treatment. There is more than one type of mange. The dogs will need to be treated with a proper miticide (repeatedly), the accompanying skin infection needs to be treated with antibiotics, the irritation soothed with medicated shampoos or creams, and if it's demodectic mange, further tests will likely be needed to further isolate the cause (as demodectic mange almost always indicates an underlying health issue as well). If it's sarcoptic mange, there's the added possibility that YOU and/or your father may also end up with it, as sarcoptic mange is contagious to humans as well.