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+-- Thread: Cleaning Discolored Slate (/showthread.php?tid=7286358)
Cleaning Discolored Slate - jihhwood - 05-19-2016
Some of the slate steps leading to our (tiny) front porch have become seriously discolored -- a very dark gray (almost black). In the past, indoors, I used muriatic acid on slate and it did a pretty good job. However, I'm a little wary of using it again, since any run-off would likely damage our shrubs. Is there a product or a "do-it-yourself" technique that can be used to clean slate? Thank you in advance. (I have used "Wet and Forget" on some discolored shingle -- worked well. But I'm not sure the black discoloration on the slate is mould.)
Re: Cleaning Discolored Slate - Snipe Hunter - 05-19-2016
Have you tried soap and water with a scrub brush?
Re: Cleaning Discolored Slate - Bob10 - 05-19-2016
do it in small patches use something to contain the run off. Doing it with a bucket should not big that hard to keep it away from plants
Re: Cleaning Discolored Slate - Herb G - 05-19-2016
Pressure washer & clean water. No soap or detergents.
Re: Cleaning Discolored Slate - Woodenfish - 05-20-2016
The black discoloration is probably mildew. Use the Wet & Forget.
Re: Cleaning Discolored Slate - JTTHECLOCKMAN - 05-20-2016
Simple Green.
Re: Cleaning Discolored Slate - jihhwood - 05-20-2016
Good suggestions, people! Thank you. I'll start with the least complex and proceed from there. Does anyone know the best way to test the slate in order to determine whether the black discoloration is mildew? Thanks in advance.