On Fri, 1 Mar 2013 00:12:19 +0000 (UTC), "Danny D."
wrote:

On Thu, 28 Feb 2013 17:07:43 +0000 nestork wrote:

It WILL dissolve cement based tile grout, but only very slowly at a 14%
concentration like you find in toilet bowl cleaners, and almost not at
all in the 6% concentration you find it in in bathroom cleaners.

I have hard water (white calcium carbonate) at something like 15ppm or so.

Do you think the naval jelly will work on that on the shower glass
without etching?

The calcium can etch glass shower surrounds. White vinegar is a
milder acid. Takes lawn sprinkler over-spray off of a car without
dame to the finish. Same in the shower.

2 cents