Stained Slate

The slate on my front porch is severely stained with marks that look like oil stains or wet spots. We've concluded that they are from the calcium chloride pellets we spread this winter. I checked the package and sure enough they warn about staining etc.

I've tried everything to remove them with no success. First I used a strong detergent. Then I tried turpentine and lacquer thinner. Finally I tried muratic acid. All with no success. (That slate seems impervious to maratic acid!).

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by johnam:
The slate on my front porch is severely stained with marks that look like oil stains or wet spots. We've concluded that they are from the calcium chloride pellets we spread this winter. I checked the package and sure enough they warn about staining etc.

I've tried everything to remove them with no success. First I used a strong detergent. Then I tried turpentine and lacquer thinner. Finally I tried muratic acid. All with no success. (That slate seems impervious to maratic acid!).<HR></BLOCKQUOTE>
You might try Vinegar It will take out some stains that other cleaner won't,It can't hurt to try it