@Twistybranch When I did A level Biology {Years ago!} I did a project on hand washing, using a 'safe' bacteria the tutor bought in for the purpose, and I tested different hand washing washes.
Povidone iodine, Hibiscrub, and cheap white bar soap and a few others.
What was astonishing was how effective the white bar soap was...an old bar, found in the college loos.
It definitely was quite impressive in my few tests on it.
Surgical scrubs were the best, but second place was the bar soap.
The unwashed hands, or just plain water were gross. They grew forests of bacteria on the agar gel.
At home I have liquid soap though, as soap dishes can get so messy.
Pears Soap, oldskool was lovely.