Review (5/5): Very effective
I paid attention to what the reviews stated and applied this carefully wearing gloves and avoiding soft skin. I left this on the thickest part of the callus for 45 seconds and then washed it off. I didn't think that would be long enough but it sure was! The callus was almost obliterated. It didn't take the whole callus off in the first round but took off about 75 percent. I would recommend this product for sure. Just be careful it's potent!