On the TV program they said 50°C, but that's pretty jot, so I think it's fine if the water is hot enough but you can still put your hands in it.
Rinse the frilly parts of the oyster, taking care not to mash the oyster meat (these ugly hands aren't mine, they're my husband's).
This much dirt comes off them.
Rinse the oysters quickly in ice water with a pinch of salt, then pat dry with paper towels.
If you are going to stir fry the oysters, I think you can skip Step 4.
I used to scrub the oysters with katakuriko or grated daikon radish, but I was never sure if it was really cleaning them. But this method really got them clean, so I wanted to share this tip with everyone.
Story Behind this Recipe
On a talk show on a local TV station here in Hokkaido, they said that you can wash shucked oysters in 50°C hot water. I tried it out right away and the oysters really became clean. I wanted to share this with everyone, so I uploaded this tip. I was listening to the program while working, so I filled the gaps based on my own experience.
Regarding the temperature of the water, if you have a thermometer you may want to measure it so that it's 50°C, but if you don't don't worry. Your body temperature is around 36°C, so the water should be hot to the touch. Bath water is around 42°C so use that as a guideline to how hot the water should feel.