Can Diet Coke Cut Through Shower Grime? We Tested This Fizzy Hack

If there's one thing I always have in abundance, it's Diet Coke. I am indeed that person hauling a 30-pack home from the grocery store on the subway. While cracking into an ice cold can of it, I got to wondering why I see so many cleaning hacks for classic Coca-Cola, to clean the toilet, polish the windows, or scour pots and pans! But I almost never see Diet Coke get the same treatment. So I decided to try cleaning the shower to see if it could hold up like its sugar-packed sibling in one of the most loathed cleaning tasks of all: the dirty shower. 

Showers can be tricky to clean for several reasons. In part, they contain several different surfaces and material types like grout, tile, glass, and metal. And they face many different types of stains from hard water to soap scum to mold and mildew. I've seen regular Coke used to tackle these sorts of messes and wanted to give my abundant supply of Diet Coke a chance to do the same. So I decided to load up a clean spray bottle with a bit of my favorite calorie-free beverage and got to cleaning, but first I wanted to understand why soda is used to clean in the first place. 

Diet Coke's most discussed ingredient is probably aspartame, the low-calorie sweetening alternative to sugar that makes the drink, well, diet. But it contains two other ingredients that are commonly found in cleaning products: phosphoric and citric acid, while classic Coca-Cola only has phosphoric acid. But don't fear. In moderation, these ingredients are fine to consume when diluted with all of that caramel coloring, water, and aspartame in Diet Coke, but they are also phenomenal cleaners. 

Phosphoric acid is often found in grout cleaners and does a terrific job of eating through grime, mineral deposits (such as magnesium and calcium), and hard water stains. It is also an oxidizer, which can tackle rust — a common issue in the shower. Citric acid is another powerful substance that can remove both metal and mineral deposits and is safe to use on grout. Since these ingredients are already diluted in the soda, you don't need to get your safety goggles and gloves out when cleaning with Diet Coke. Anyone looking to reduce their use of harsh cleaning chemicals may want to go down this route. Plus, Diet Coke is carbonated, and who doesn't like bubbles in their cleaning products? 

I wanted to see how the Diet Coke did completely on its own, so I didn't add any other ingredients to the spray bottle. It had been a few weeks since my husband last cleaned the bathtub after a disastrous attempt at cleaning my oven grates in the bathtub with coffee grounds, so it was definitely in need of a thorough scrub down. I doused all of the different surfaces with Diet Coke, paying special attention to soap scum buildup in the grout of the wall tiles, hard water stains on the hardware and glass door, and gray grime on the bottom of the bathtub. I let the Diet Coke sit for just a few minutes before going at it with an ice water-soaked Scrub Daddy sponge, available in a pack of four from Amazon for $12.71. 

I started on the wall tiles and saw the yellowed soap scum and pink something (possibly mildew!) come off immediately. As for the hard water stains on the shower doors and handles, I didn't have quite as much success. The Diet Coke and scrubber method made the hardware look slightly clearer, but definitely not sparkling clean. In the bathtub itself, I was able to scrub away some of the gray spots pretty well and thought they were gone entirely, but after rinsing and drying, I saw there were a few stains left behind. 

Diet Coke as a shower cleaner was not a total bust. I was very impressed with how it removed soap scum, which was very apparent on the sides of the bathtub where we store products, as that's where excess products leak out. The Diet Coke ate through this like a champion. While it did okay at removing some of the grime elsewhere in the shower and tub, it couldn't compete with commercially available shower cleaners, especially against hard water stains. My hardware and glass doors were still left foggy, and I needed to give my tub another scrub down with a stronger product afterward. 

The Diet Coke also wasn't easy to work with. It doesn't lather like actual cleaning products, so even when mixed with hot water, I felt like it didn't go very far at all. It also required a lot of elbow grease to get grime to lift, so I was tired and sweaty by the time I'd scrubbed and rinsed the entire area. Finally, even with some of the physical debris removed, Diet Coke just didn't give me that "brand new shower" feeling that I was looking for. Though things were cosmetically cleaner, I knew the shower wasn't sanitized, and that the soda did nothing to fight against germs and bacteria. In the end, Diet Coke isn't the genius shower cleaning hack I'd hoped for.