The soap under the sink
Most household cleaning is one surfactant wearing different perfumes, and fragrance sits near the top of the contact allergens dermatology tracks. A castile concentrate covers the sink, the floors, the dog and you, unscented if your skin has opinions.
The dilutions
Roughly a quarter teaspoon in a cupped hand for face, a tablespoon per sink of dishes, a quarter cup per bucket for floors, and a half-and-half squirt bottle for the shower. Castile is a concentrate, and most disappointment with it is someone using it neat.
Where it does not work
Never with vinegar or lemon in the same bottle. Acid plus a true soap breaks the soap back into fatty acids, and the white curd left behind is the reaction, not dirt. Use one, rinse, then the other if you want both.
Hard water
The same reaction happens slowly with calcium in hard water, which is where the film on shower glass comes from. Sal Suds is a detergent rather than a soap and does not curdle, which is why it is the one to use for floors and laundry in a hard-water house.
Fragrance
Contact dermatitis patch testing puts fragrance mix among the most frequent positives year after year. If skin is reactive, the unscented bottle removes a whole category of suspect at once.
