Putting mangoes in a simple salt brine may not work for all kinds of mangoes with thick peel. The use of vinegar helps in breaking down the tough skin. The sugar and salt combination is a age old practice for pickling as the hypertonic solution makes the mango loose its water content and shrink. The high concentration liquid then enters the fruit cell. Adding mangoes to boiling hot water is also plays an important role.it kills the bacteria and destroys any chance of mildew formation on the skin and breaking down the flesh without actually cooking the mangoes. Thus preserving the mangoes better.