Sure, but how? I’m left guessing at which parts to scrub how much, possibly ruining the effect of the washing.
If you want to be precise and thorough in your handwashing, some studies will give you more details. Shi, O’Donoghue, et al (2023) did a nice observational study on how washing technique affects cleaning results. The study uses the same seven steps of scrubbing as the Hong Kong Recommendation. Figure 2 shows the estimated washing effectiveness as a function of the duration of each step. If we take the peak of each such curve, we conclude that optimal handwashing goes like this:
Wet hands
Apply soap
Rub palm-to-palm, 4 seconds
Rub palm-to-dorsum, fingers interleaved, both ways, 6 seconds
Rub palm-to-palm, fingers interleaved, both ways, 2 seconds
Rub backs of fingers in palms, curled together, 4 seconds
How to wash your hands precisely and thoroughly
Link post
Common instructions on handwashing are too vague for me.
Sure, but how? I’m left guessing at which parts to scrub how much, possibly ruining the effect of the washing.
If you want to be precise and thorough in your handwashing, some studies will give you more details. Shi, O’Donoghue, et al (2023) did a nice observational study on how washing technique affects cleaning results. The study uses the same seven steps of scrubbing as the Hong Kong Recommendation. Figure 2 shows the estimated washing effectiveness as a function of the duration of each step. If we take the peak of each such curve, we conclude that optimal handwashing goes like this:
Wet hands
Apply soap
Rub palm-to-palm, 4 seconds
Rub palm-to-dorsum, fingers interleaved, both ways, 6 seconds
Rub palm-to-palm, fingers interleaved, both ways, 2 seconds
Rub backs of fingers in palms, curled together, 4 seconds
Rub around both thumbs, 5 seconds
Rub fingertips in palms, both ways, 6 seconds
Rub around both wrists, 6 seconds
Rinse
Dry
The linked post includes a video to teach this procedure.