Asked on Apr 27, 2017

North side front steps green from lack of sun, what can we do?

Kathy GuyShirley HeikkinenJudy Ferrell


heavily stained limestone front step are green and black from lack of sun. How can I clean these steps. I have already used acid on them and scrubbed the with cleaning solution. Any ideas?
3 answers
  • Judy Ferrell
    on Apr 27, 2017

    email Ask This Old House. They will maybe have a suggestion. They may even come help.
  • Shirley Heikkinen
    on Apr 27, 2017

    I found this when I did a google search "You can make a poultice by taking 3/4 cup of flour and adding little amounts of hydrogen peroxide until you have a paste. Apply the paste and allow it to dry, which may take as long as a day or two." There are sealants available once the steps are clean.
  • Kathy Guy
    on Apr 27, 2017

    If you don't have a power washer, they are cheap to rent for a day. I power wash the conceete steps, walk way and driveway and then you can seal them. It is not hard and it is amazing how the concrete comes up like new!
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