# Forum Home Renovation Paving  lichen/moss on indian sandstone

## ray3103

hi all. i have the start of lichen on my teak indian sandstone. eventhough north facing, the melbourne weather this year has not helped with a bit of green appearing as well as the gry/black lichen.
tried karcher but did not have much change, also did not want to damage the integrity of the stone by going too close. tried liquid bleach diluted 1:10 approx on some steps ; it helped a little but when dry, appeared some of the stone looks too pale. so i got worried and stopped. next step ? pool chlorine ? but there are othere suggesting damage will occur. 
stone was initially sealed with the clear seal.
anyone cured this ailment before?

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## jamc0984

Diluted chlorine wont damage the stone. Chlorine will also kill the moss. You would probably be better and safer to buy a proper chlorinated cleaner like Maestro from Klen international. At least they have been tested and offer ratios etc.

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## ray3103

thanks jamc0984. will try to get my hands on some maestro.
i agree the ratio bit is bit tricky as too concentrated may cause damage. thanks for the help.

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## chalkyt

The "Big Green Shed" carries a NZ product called 30 seconds. It is sodium hypochlorite and 47 secret ingredients. I lived at Turramurra in Sydney (regularly the wettest suburb) and had sandstone paving all over the place... often green! 
30 seconds worked well although it had to be reapplied from time to time.  :Smilie:

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## johnc

If you want to use a` mild abrasive you can use a piece of cuttle fish with water, it will clean without damaging the stone, but it may take the edge of the polish if it as a wax. try the chemicals first and see how you go.

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## cherub65

Liquid chlorine , diluted 1:10 will do the trick

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## Oldsaltoz

Wet and forget is a product that has some good reviews.

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