Grey Water Safe Cleaners for Soap Scum

I have been neglecting to clean the bathtub in my bathroom for several months so there is now a disgustingly thick layer of soap scum on the walls of the tub. Although my house is not currently linked to a grey water system, the severity of the soap scum has me wondering if there are effective cleaners that can be used to remove soap scum that won't harm the surrounding water system when drained through a grey water area.

I have just looked up the chemical nature of soap scum and it appears that the main componenta are calcium stearate and magnesium stearate. It has been about two years since I last studied chemistry so I don't remember what cleaning products will disolve soap scum.

My best suggestion is a paste of vinegar and baking soda.

If the problem is really bad you might need several application or maybe use the baking soda as a cleanser to scrub the soap scum.

Anne Miller wrote:My best suggestion is a paste of vinegar and baking soda.

If the problem is really bad you might need several application or maybe use the baking soda as a cleanser to scrub the soap scum.

How about washing soda? This is sodium carbonate. Washing soda is a much stronger base than baking soda so it's often used as an electrolyte for rust removal and for clothes washing.

I have always used vinegar and/or baking soda to clean my whole house.

I have only used washing soda in the washing machine years ago before we had a septic system. So I don't know how it will clean a bathtub.

I like baking soda because it is slightly abrasive so the baking soda acts as a cleanser.

It is my understanding that washing soda is not recommended for grey water systems.  Maybe because of the salt content.

My greywater all goes straight to some trees and I've lived with greywater systems for over 25 years.

Soap is generally alkaline. I find vinegar works well. I recently cleaned some built up stains on two porcelain sinks in my house. I had scrubbed with soap or detergent once in a while, and while that works great on the tub (we scrub the tub quickly after every use), it wasn't working on the two-year-old built up stains in the sinks that weren't getting such regular attention. Then I scrubbed with vinegar and it made a dent, but after several minutes of elbow grease I got fed up, gave up, left the green scrubby on top of the stain, and dribbled a little vinegar on it. When I came back a few minutes later it took just a moment of scrubbing and was suddenly sparkling as clean as new. Very gratifying.

I don't try to be perfectly precious about my greywater. At the school I lived at for over 20 years, the biggest and healthiest trees on the campus -- by far! -- were the willows that get all the greywater. This is a residential school for teenagers, and we used standard common Indian detergent bars for dishes, commercial detergent such as Tide for laundry, and did not try to control the "products" that the students or staff use on their hair or skin. And the willows on the greywater canals have been thriving on it for over 25 years.

Ana Edey in her book Solviva talks about a similar tactic she used in her flushing worm bin toilet, using commercial toilet cleaners and it never seemed to hurt the worms in the bin or the pine trees that the effluent went to in underground perforated pipes.

At my house, the first two trees that get the greywater are willows, and it's only been 4 years but they're lovin' it. My housemates and I don't use too many industrial personal products, but we do use commercial soap, shampoo, lotion, toothpaste, dish detergent and bathroom scrub detergent. I guess we use those detergents sparingly. We're almost finished with the second bottle of "Harpik" after 4 years, and it gets used after most bathtub soaks, and maybe once a year all over the bathroom walls, but I guess it's sparing use. (Oh, the shower is separate from the tub, and both are in a fully tiled room).

Art Ludwig's helpful and important book on greywater systems points out that topsoil has a very rich, diverse and lively microbiome, so surface greywater systems digest soaps etc quickly and effectively.

It also depends on concentration. If you use water luxuriously, the products will be diluted enough that the soil can digest them.

Three cleaners I've seen mentioned so far are baking soda, vinegar, and lemon juice. Two other interesting cleaners I'm curious about are wood ash lye and citric acid. The main problem with wood ash lye is that it is very caustic and not safe to inhale or keep around children. Citric acid is a common food additive and is the active chemical in lemon juice when it is used as a cleaner. The problem I see with diluted citric acid is that the substance cannot be practically extracted from citrus even with a high school chemistry lab so it would have to be purchased from a chemical supplier.

What about limonene, would that work as a substitute for citric acid?

https://permies.com/t/117228/permaculture-home-care-cleaning/purity/Grease-cutting-lard-soap-borax#953273

Alkalines help oils be able to mix with water and thus be lifted and washed away. Soap, lye, wood ashes, and many clays are alkaline.

Acids dissolve alkaline deposits such as calcium deposits and soap scum. If you want a homemade acid cleaner then homemade vinegar is an obviously easy choice.

You could try one first (either an acid or an alkaline), letting it soak on for a few minutes and then scrubbing. After rinsing it off, if you feel it didn't do much, then try the opposite (acid after alkaline or vice versa).

And then please don't forget to come back here and let us know what worked!

Anne Miller wrote:What about limonene, would that work as a substitute for citric acid?

https://permies.com/t/117228/permaculture-home-care-cleaning/purity/Grease-cutting-lard-soap-borax#953273

I almost forgot that lemons have both D-limonene and citric acid in them. This makes them even better of a cleaning agent than I originally thought.

Interestingly, trifoliate oranges (Poncirus/Citrus trifoliata), because of their low pH, might also be suitable for use in household cleaning. Due to the resinous nature of the fruits, they may have even more turpenoids present besides D-limonene that could be useful in household cleaning. The fruits are also naturalize throughout the southeast United states so they can easily be foraged when they are ripe. The juice could then be frozen for later use either for orange-aid or for household cleaning.