How do we restore the shine to a granite surface?

May 7, 2007 7:37 AM

Granite is impervious to most things, except...

dishwasher liquid. My husband ran the dishwasher last night but accidentally spilled some of the detergent on our black granite counter and did not clean it up. I saw it this morning, it had dried to a white powder. When I washed it away, it left a quarter-sized dull spot in an other otherwise shiny and beautiful surface. It's not scratched, so I'm not sure what happened. The stuff doesn't do that good a job on dishes! Granite cleaner did nothing. What to do, what to do? I do not want to make it worse.

posted by clarkstonian to home & garden (9 answers total)

Most dishwasher liquids have fairly mild agents in them (although the Costco brand seems to have bleach), so I doubt that it hurt the granite.

I bet what is more likely to have happened is that there was some clear coat or sealer on the surface of your counter that was applied to make the granite look shiny, and that the coat was damaged.
posted by scblackman at 7:44 AM on May 7, 2007

Did it actually stain the granite itself or did it just affect the sealant? I highly doubt it damaged the granite, but I'm not an expert. You may only have to polish it.
posted by arco at 7:44 AM on May 7, 2007

Look at the underside of one of the edges of your counter. See how rough it is? Yet it's not damaged, it just hasn't been finished like the top of the counter. You probably just need to re-polish / re-seal that spot.
posted by chundo at 7:47 AM on May 7, 2007

A number of dishwasher detergents will contain alkaline agents; you can restore the countertop with sealant, or by have a floor service specializing in flagstone provide an estimate.
posted by Smart Dalek at 8:06 AM on May 7, 2007

It doesn't seem to be a stain - it's almost like a thumbprint - a swirled design - etched in the surface. If it's a sealant that is damaged, can we seal a small spot, or should we wait until there are more of them (inevitably!) and have the whole counter surface redone? Is there any way to tell if it is a sealant? I wouldn't have thought dishwasher liquid would do so much damage. I've tried granite polish, and that didn't do anything.

It's not in a spot where you could hide it with a vase or a fruit bowl, and it's very visible.
posted by clarkstonian at 9:58 AM on May 7, 2007

Was it a citrus dishwasher detergent? If so, are you sure you have pure granite or do you have the 'man-made' stuff? Anything acidic (citric acid especially) will etch and ruin the man-made stuff, which is pretty much held together with the sealants that they put on the surface of other granite.
posted by SpecialK at 12:16 PM on May 7, 2007

You can spot-seal, but if you have a sealed granite counter it's a good idea to reseal the whole thing on a regular basis anyways (probably yearly if you use it frequently).

Don't leave it unsealed for long - it could get permanently damaged if you spill something harsher on it.
posted by chundo at 12:37 PM on May 7, 2007

You might want to search for info in the Kitchen Forum on GardenWeb or ask there, too. I had a problem with some oil stains on a granite countertop, and I found my answer (poultice of acetone) there. One frequent poster, stonegirl by name, had especially great answers.
posted by Robert Angelo at 12:39 PM on May 7, 2007

It's definitely real granite - and the other side is fresh-out-of-the-ground rough. Yes - it was a citrus detergent. It was lemon-fresh.

I'll check out the Kitchen Forum - that's a great idea. I thought I might try calling some of the granite retailers in the area, too. We're really not hard on the counters at all - very careful to use cutting boards and trivets - it's the first real mark in 4 years, but maybe resealing it is a good answer.
posted by clarkstonian at 7:04 PM on May 7, 2007