It works well but be careful. . Two ingredients, Ammonium Hydroxide and Propylene Glycol, are carcinogens. However, given how long this product has been on the market (since 1914), if it could be directly linked to cancer I highly doubt it would still be available. I wouldn't blame anyone for not using it for that reason, but it is FDA approved and, as far as I know, safe if used correctly. . That said, for me this worked exactly as advertised. I apply it to my face while dry, leave it on for a minute or two, and wash off with a warm washcloth. It cleared the blackheads on my nose as well as anything else I've ever used (Queen Helene Mint Julep Mask, ProActive, scrubs, peels, oil cleansing method, etc.). That said, be sure to use it in moderation. If I use it more than once a day, my skin will become very red and irritated. Use it at most once per day, reduce to every other day if you experience any irritation or redness. . I can't give this a 4 or 5 due to the harmful chemicals but it does work if you're careful with how you use it. It is certainly an aggressive treatment.