Potassium permanganate (spelling?). Get a small container from over the chemists counter. Dissolve about a match head size amount in a bowl of water about 1 inch deep. The water will be bright purple, pop your feet in and soak them for about 10 mins, colour of water will change to a reddish hue. Take feet out, dry on an old towel. Don't have the water too deep as it can cause slight discolouration and you dont want it to show. Do this for a few days in a row. Don't spill the water whatever you do. This is an old fashioned remedy and it does work. If you need some advice, best go to an old traditional independent chemist, you probably know the sort I mean.