Homemade remedies like a dilute ammonia and water solution may "work" to remove the soap scum, but just like the ingredients in common store-bought shower cleaners the ammonia will cause marble etching leaving dull and discolored spots or ruining the entire finish on the marble or travertine tile. So... these are not a viable choice.
Cleaning with "Soap & Water" produces a predicament. This mix is often recommended as a cheap and easy method of cleaning marble and natural stone.
While most soaps won't damage stone, (although some are acidic enough to etch marble) you simply cannot completely rinse the stubbornly sticky soap residue off the floor
or countertop surface.
It's important to note that even with all that water washing soap away in a shower... soap scum still builds up on the shower walls and floor.
Soap cannot be avoided in the shower, but it should be for cleaning granite countertops, marble and other stone.
The soapy residue forms a film on your granite & marble countertops and floors (just like in a shower or bath) making them look dull and dingy.
At this point, "general" stone or marble cleaners will not be potent enough to remove soap scum, which leaves homeowners wondering what the heck is happening.
You simply need to use the specially-formulated "Soap Scum / Hard Water Remover" for natural stone suggested above. As you might have guessed... it is highly effective at removing hard water deposits as well.
Mineral build-up or scale from hard water behaves and looks similar to soap scum. Luckily, the one cleaner does double-duty.
Spray it on and let it soak for 10-15 minutes into the on the soap scum or hard water deposits. Then scrub with a soft-bristle brush. Repeat if you have a lot of build up.
Once you've thoroughly cleaned the surface it won't be so difficult to keep soap scum from developing with frequent light use of this product.
One last point... Soap scum and marble etching can sometimes be difficult to distinguish. Both look like dull, whitish areas. To correctly diagnose which you have, scratch with a fingernail or other soft/plastic scraper. You should be able to scrape off soap scum or hard water deposits.
There is "soap scum" appearing marks where the dish drain board sits on the granite countertop.
We cannot clean it away. I did not put a drain board under the dish drain, thinking granite could not be damaged.
Is this because the installer did not properly seal the granite countertops? The rest of the counter top is fine. The counter is about 10 yrs. old.
How do I remove this soap scum?
It may be soap scum, but it could also be hard water deposits.
Both can form a whitish type film that can be very tenacious and can't be removed with general methods for cleaning granite countertops.
Soap scum is waxy and hard water deposits are more crusty.
You'll have to use a specialty stone cleaner, but fortunately the same granite cleaner will take care of both soap scum and/or hard water.
We recommend using this Soap Scum / Hard Water Remover made just for this issue and safe for use on marble and granite countertops, showers, baths, etc.
And to dispel any misconceptions... granite can be damaged. Every single type of countertop surface available on the market can be damaged... some more easily than others.
Granite is certainly one of, if not the hardest to damage, but it can occur. So, proper granite countertop care and maintenance is still important... it's just easier than other surfaces.
Try the Soap Scum/Hard Water remover, however, if it turns out that you indeed have a "stain" (darker spot of something absorbed into the surface), then follow the directions in the Removing Granite & Marble Stains ebook.
Sealing will not prevent the build-up of soap scum or hard water deposits since these occur on the surface of the stone. However, a sealer will help prevent absorption and staining that sometimes can occur with prolonged hard water deposit exposure.