Bleach, actually. A small amount of bleach added to spoiled milk makes it taste brand new. The government actually suggested this in a few countries for a while.
Plaster in flour was common enough that after the miller, the middle men, and then the baker all added a cut, there were loaves being sold with less than 20% flour in them. The result was mass malnutrition.
Also, and this is a spicy one but backed by basic economics, regulations are a required element to capitalism. The notion that deregulation is pro capitalism is a misinterpretation of the idea that markets are self regulating. A free market is one that is free of corruption and unfair business practices. Which cannot exist without regulations and the enforcement of those regulations. All our current economic woes are the result of straying away from proven economic theory (mostly deregulation) to the right allowing the corruption of the marketplace and emergence of a strong oligarchy.
That’s not true at all. Sometimes the cost is more for men. But almost universally the costs of the same item are more for women than for men. The running joke is that if you take the same volume of shaving cream, stick it in a taller narrower bottle, and add a label with purple and butterflies; you can slap a higher price on it.
Look at pockets. Women rarely find clothes with pockets. When they do the pockets are usually very inadequate. Their pants use less material but cost more.
Alternatively, their clothes often take more materials to clean, so drycleaners cost more for women’s clothing. Haircuts cost more for women but they usually take more time and materials as well. So there are often hidden considerations that complicate how we judge and view this matter. At the end of the day it costs more if manufacturers can get away with charging more without losing sales.