Here's Why You Should Never Mix Epsom Salt With This Popular Cleaning Solution

Castile soap is a hard-working addition to your kitchen and bathroom. The vegetable-based soap is both nontoxic and hypoallergenic, making it a perfect cleaning solution for those with sensitive skin and allergies. In addition to being a personal hygiene go-to — a one-stop shop for shampoo, body wash, shaving gel, and more— you can also use Castile soap as a household cleanser, from the dishwasher to your washing machine, to your countertops. It works so well, you might think, "Hey! Let's up the ante!" and try to combine it with another cleaning workhorse, Epsom salt. But marrying the two can actually make your cleaning task take even longer when you have to clean up the mess that results from your DIY cocktail.

While combining Epsom salt with your Castile soap might seem like a good scrub-a-dub-idea, it's actually a recipe for a scummy disaster. Epsom salt, also known as magnesium sulfate, has an acidic pH. Soap, including Castile soap, is alkaline. When you combine the two, a small reaction happens, resulting in a hard-to-clean substance known as soap scum. It's the same reaction that happens when your shower's hard water — water full of magnesium — mixes with your shampoo and leaves stubborn residue on your tub. Looking to do more of a deep dive into your tile? Here's how to deep clean your bathroom and keep it clean.

When you mix Epsom salt with water — which is what we assume you're doing when you clean with it — you are putting magnesium into the water, making the water "hard." The magnesium reacts with the soap to form what's called a precipitate, or non-dissolving substance. That's the soap scum you see all over your shower walls. Soap scum isn't just unsightly. When hard water mixes with soap and goes down your drain, it leaves a trail of hard soap scum all along your pipes. Soap scum is also the perfect home for bacteria and mold, which can leave your sink or shower with discoloration and nasty odors. 

While it looks similar to calcium deposits, you can identify soap scum by its soft and spongy texture. Luckily, soap scum is easy to treat with both store-bought and DIY remedies. Try using white vinegar, or combine baking soda and vinegar for a fun chemical reaction that will make removing soap scum easy. Those are just two of the eight easiest ways to clean soap scum off your bathroom surfaces.

While the Castile soap and Epsom salt combination is a no-go, you don't have to remove Castile soap from your cleaning rotation forever. In fact, there are other substances you can add to Castile soap to increase its efficacy. If you're looking to make a gritty cleaner to really scrub down your surfaces, turn to baking soda. Combine your Castile soap with a small amount of baking soda and mix into a paste, then use it to scour countertops, showers, and even dishes. 

Find yourself in need of laundry detergent? In a pinch, mix one bar of hand-grated Castile bar soap plus one cup each of baking soda and washing soda. One tablespoon of the mixture should be enough for most high-efficiency washing machines. 

If Castile soap is part of your personal hygiene roster, try mixing it with some olive or coconut oil to create a moisturizing hand soap — Castile soap will even foam if you add it to a foaming hand soap dispenser — or add a few drops of scented essential oils to concoct a good-smelling body wash. You can even use Castile soap for more than cleaning. If you've got a green thumb, check out these genius reasons you should be using a bottle of Castile soap with your plants.