WTF? Are you saying that some people's sweat have so much acidity that it disintegrates shoes??? What's this? Prequel to some Marvel super hero story..Sweat does differ between individuals but it's still sweat. And the only reason that the variance can be detected is due to the advent of modern day high precision instruments.And even if what you said is true about all those acidity, shoe cream won't save you; better douse some baking soda to soak up the acidity.