Generally speaking, blanching refers to putting ingredients in boiling water for a certain period of time and then picking them up. For oysters, the main purpose of blanching is to remove the fishy smell and impurities of oysters. The function of adding salt is to improve the taste. The specific time and the amount of salt need to be determined according to personal tastes and preferences.

Generally speaking, oysters should not be put into boiling water for too long, about 30 seconds to 1 minute. Too long blanching will make oysters overcooked and taste bad. As for the timing of adding salt, it is generally possible to add an appropriate amount of salt before or during blanching.

It should be noted that different recipes or cooking methods may have different requirements. If you have a specific oyster recipe, you'd better refer to the steps and suggestions in the relevant recipes.

To sum up, the blanching time of oysters can be customized according to personal preferences and recipe requirements, generally about 30 seconds to 1 minute, and the salting time can be carried out before or during blanching.