talk to a brick layer. Etching, that you can't even see is NOT damage on a Mexican Satillo paver. Go spend a buck on one and try it. P.S. Just because you don't know something doesn't mean it doesn't exist. You certainly would not want to clean a glazed tile with muratic acid. Satillo is another story. They are installed in an unfinished state. They can be safely cleaned with a weak solution of muratic acid.