On the TV program they said 50C, 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.