Soap doesn't do anything
Soap is one of the biggest scams perpetrated on the American public since the "civil" war. The truth is soap really doesn't even do anything, more of a lubricant than anything else. It's just that we've all been taught to use soap so we never try it any other way. If you want to find out for yourself, one day just take a shower without soap. You'll get clean, I promise. The same goes for shampoo. If you have some really ground in dirt every now and then, spread baking soda on it and apply vinegar directly, it's 100 times as effective as soap.