On Thursday, June 18, 2020 at 10:55:12 AM UTC-4, wrote:
Not to be snarky, but you do not wallow much in grease, do you? No detergent under those conditions just spreads a very fine coating of grease on everything. True, though, there *is* less on the clothes thereby.

I thought we had gotten away from pounding clothes with rocks streamside.....

Peter Wieck
Melrose Park, PA

No, you're quite right, if our job or hobby involves heavily soiled clothes we need the right amount of soap. Perhaps even in a climate where we sweat a lot.

But for the average person with an indoor sedentary job, student, etc., who changes clothes on a daily basis, the clothes never get very soiled.

Some years back there were these magic laundry balls, "bio ceramic," that were supposed to work without soap. When they were tested, they worked. So that lab also tried washing without them, and that worked too. There is probably enough soap residue on clothes to get several washes.