Generally because there are fruit fly larvae in the prunes with salt water soaking, do not want to eat the fruit fly, can be dealt with in several ways:
First, soak in lightly salted water for no more than half an hour.
Second, soaked in white wine and then rinsed with water. (Soak for no more than 15 minutes)
Third, scald the prunes with hot water to force these bugs out.