My father, 86 years old, had knee replacement 6 years ago. No diabetes. Has hypertension and being treated for it. Last 2 years, there was initially blackening of toe nails. Last year left foot below knee was swollen and oozing. Doctor ruled out DVT. He said it was prob cellulitis. Treated with antibiotic and anti allergic medicine. No oozing now, but there is still a little swelling on left foot. Antibiotics and anti fungal medicine is going on for past 2 weeks. I cleaned the legs with hydrogen peroxide and the legs are now clean. However, there are still many black patches on the skin on the legs and thighs. Should I clean with hydrogen peroxide or would potassium permanganate be better?