# How to clean Black slate



## CanCritter (Feb 9, 2010)

just did a Granite reface on a fireplace that they added a zero clearance fireplace to ..they have a thin black slate hearth that runs the full length of the fireplace..over the years it has seen neglet and lack of care..altough surface area is rough and dirty ect is still in good shape....what would be the best way to clean this stuff up..only thing that comes to mind is light sandpaper and lemon oil if l remeber correctly...thoughts?

Thanx Kindly
Critter


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## Old Grumpy (Mar 11, 2009)

Rough slate or honed? Cleaning dirt/old sealer or scratches and stains? I've been around a lot of slate and have seen it mostly cleaned with TSP or occasionally a dilute muriatic acid. If it was a smooth surface that needs resmoothing silicone carbide sandpaper used wet with a sanding block will work and keep the black dust down. It takes a lot of sanding to smooth a large area though. The few pieces I've done myself (coffee table top, some accent slabs) I took to 400 grit. My wife does some work with slate and runs it up to 800 grit. I used terrazo sealer on the table top and it has stood up well for a long time. My wife seals her work with a thinned satin or gloss polyurethane in a very thin coat.


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