My apartment has terribly hard water, plus a shower with glass doors. What does that make? Instant soap scum. I went looking for the best cleaner that would cut through soap scum, plus remove the underlying hard water spots. After careful study, I found a winning product.
First, some context and explanation. Hard water spots, also called “lime scale,” occur when droplets of hard water dry on a surface. The water evaporates, leaving the minerals behind. On vertical surfaces this looks like overlapping scales, or shingles. Hard water is problematic for many reasons (I’m going to tackle this topic at large in an upcoming post), but in the bathroom it’s trouble because the mineral scales give the soap scum something to stick to, and soap scum build-up happens much faster. Soap scum is a combination of soap plus minerals, so not only does the lime scale make the soap scum stick, but hard water produces more soap scum overall.
This soap-scum-plus-lime-scale combination presents a problem for traditional household cleaners. Most general household cleaners are alkaline (or have a pH level greater than 7). The foundation of many cleaners is bleach, and bleach has a pH level of 13. Soap scum needs an acidic cleaner to break up its minerals, however. With my thick soap scum, due to very hard water, I needed an even more specialized product. I knew from experience something like Tilex (which pledges to remove soap scum) just wasn’t going to cut it.
For this test I scoured housekeeping books and online message boards to assemble as many product recommendations as possible. I knew any cleaner that pledged to remove hard water spots would also work on soap scum, so that is what I searched for.
Here is what I found:
- Some people online speak highly of Bar Keepers Friend
- Martha Stewart recommends Lime-A-Way.
- Another housekeeping expert endorses vinegar.
- Others online speak highly of Kaboom. It pledges to “remove soap scum, dirt, hard water stains, calcium, lime, grease and grime.”
- CLR (Calcium Lime Rust) is the other widely available anti-hard water product.
- Finally, for a control I included the strongest alkaline cleaner I had – toilet bowl cleaner with Clorox.
The setup: I marked off six areas on my very dirty shower door. I decided for this test I would simply dab or spray on the cleaning product and let it sit for two minutes. I’m not opposed to using some elbow grease when cleaning, but I wanted to know how strong the product was by itself. The vinegar-endorsing expert suggested using a 1:1 mixture of vinegar and water, but I opted for straight vinegar. This isn’t sulfuric acid we’re talking about here. At the end of the two minutes I wiped off the cleaning product with a clean paper towel and studied the results.
Findings: The angle of the above photo is perfect to study the soap scum component of this test. All five of the specialty cleaners, including the alkaline toilet bowl cleaner (far left) did a good job of removing soap scum. Straight vinegar (third from right) barely penetrated the scum. Let’s look closer to find a winner.
Studying the cleaning test head-on provides definitive proof. While both Bar Keepers Friend and Lime-A-Way did an admirable job with the lime scale, the toilet bowl cleaner failed. Note how hazy the glass is. it’s clear the vinegar hardly did anything. And while Kaboom cut through a lot of soap scum, it still left those pesky lime scales behind. CLR did pretty well, but it doesn’t look to be better than either Bar Keepers Friend or Lime-A-Way.
To my eye, the results were a toss-up, with Bar Keeper’s Friend and Lime-A-Way in a dead heat. I let the ease-of-use question settle the matter. While Lime-A-Way comes in a spray bottle, Bar Keeper’s Friend requires sponge application. Listening to my spray bottle prejudices, I opted to clean my shower with Lime-A-Way.
A few minutes later, the results were striking – I could actually see through my shower door! Closer inspection (note the photo at left) revealed unsatisfactory results, however. While the scaling was much better and the glass door was see-through again, there were still obvious water spots on the glass. My selection backfired on me.
To settle the matter, I returned to the second and third-place finishers – Bar Keepers Friend and CLR. Both require sponge application, so I coated each pane of the sliding door with one cleaner. I waited and scrubbed, knowing this tough residue likely wouldn’t just dissolve.
This time I had total success. While the CLR didn’t change anything, Bar Keepers Friend reduced the residue to almost nothing. In places where I had scrubbed particularly thoroughly, the glass was completely clear.
Bar Keepers Friend traditionally comes in a powdered can, like Bon Ami or Comet. I opted to use their “multipurpose cooktop cleaner,” which is in thick liquid form, and I knew would be easier to use. By cleaning my glass doors with Bar Keepers Friend I was going off-label. The bottle says, “To prevent scratching glass … use sparingly and rub gently with damp sponge.” I did not use sparingly and I definitely didn’t rub gently, but I also didn’t see any scratches on my glass.
I finally found a product that could handle my admittedly filthy shower doors. The price point sealed the deal – I purchased one 13-ounce bottle of Bar Keepers Friend for $3.29, and still have more than three-fourths of it left. To do an equivalent amount of cleaning I needed almost a whole bottle of Lime-A-Way, costing $5.49 a bottle.
One more benefit of Bar Keepers Friend: I had to stand in the shower, with the doors closed, to clean them. Fumes from the sprayable Lime-A-Way quickly built up, but breathing wasn’t an issue when using Bar Keepers Friend.
In the end, this was one Internet factoid that proved to be worthwhile to follow up. If you have thick soap scum, hard water spots or both, Bar Keepers Friend Multipurpose Cooktop Cleaner should be the first product you choose.
(One important note: You should never use an acidic cleaner to remove soap scum from stone, like marble. The acidic properties that remove the scum will also degrade the finish on your stone. Opt for ammonia instead.)