Autor claims "soap" is not toxic. Real soap is not really toxic, but what he is using is dishwashing detergent, which is usually notably toxic and not biodegrad

Autor claims "soap" is not toxic. Real soap is not really toxic, but what he is using is dishwashing detergent, which is usually notably toxic and not biodegradable. I wouldn't pour a bottle of it my back yard. Also, it typically coats greasy surfaces, and probably waxes as well. It makes it easier to wash off grease, but if you don't/can't, the detergent stays there.