I am looking for guidance as to how I might clean/refinish UNpolished granite. Here is what happened:
I just completed tiling the undercounter area of our kitchen. I had found a company in Texas called Antiquestone (http://www.antiquestone.com/listellos_3.php) for the decorative listellos. They used black polished granite and etched in designs. It makes a beautiful look with the contrast from the black polish versus the soft grey background.
I covered the listellos with blue painter tape and tiled the rest of the undercounter walls with tumbled marble. The marble tiles were then sprayed with an enhanced sealer (the granite listellos still covered). After 10 minutes, the sealer was wiped off then allowed to cure overnight.
The next day the tile was grouted (listellos still covered) and excess grout scraped. After the grout had begun to set up, I removed the painter tape covering the granite and touched up the grout next to the granite. At this point everything was still OK.
The tile was sponged of grout. And, only minimally did I sponge the granite.
Later on, we noticed that there were large "sploches" of darkened gray on the listellos (looking like they were wet). But, the wet look never went away. When the gray looks wet, it is very dark and there was NO contrast to the polished design.
It is very erratic where the sploches are. But they are scattered throughout the layout.
So, I have two major questions:
1) What in the world may have happened to cause the discoloring of the etched (NON-polished) granite? The polished area is fine.
2) Any ideas on how to get the dark splotches back to looking a soft gray?
If you click on the link above, you can see some sample black granite listellos to understand what I am talking about.
The sealer could have gotten on the paper tape and soaked through in spots or the diluted grout could have caused the splotches. If you have any scrap pieces left, try to duplicate the problem on it. They have products that you can use to remove grout that has dried on tile. You can also try a dilute solution of muriatic acid on the scrap piece. It will react with the grout to clean it off. Follow all the instructions and wear protective equipment. This is a dilute version of hydochloric acid. Still burns your skin though.
For the sealer I would contact the manufacturer. They may have a stripper.