Maybe you could try to use a little less by soaking a sock and wearing it? You might even put a plastic bag around your foot so you can move about. Or just take a little while to age more urine. There's plenty :) Usually I Re-use the urine I used for my hair for my feet, but not the other way around, even if my feet are totally clean, but that is just the way I do it. I like the sock method, yet soaking is also very good. Fresh can be used with good results too.