Place all the maavadu in the jar.
Drizzle castor oil on top. Close with lid and shake well for the maavadus to get coated well with oil.
In a mixie jar, add rock salt and powder it.
Open lid and add the powdered salt. Once again close with lid and shake well. The salt will stick well to the oil coated maavadu.
Take mustard seeds in the same mixie jar and grind to a fine powder. Add red chili powder, turmeric powder and pulse few times to mix well.
Open the lid and add the powered spices. Close with lid and once again shake the vessel several times for even distribution.
Close with lid and keep aside.
From the second day on shake or stir the mangoes twice a day daily, preferably during morning and evening.
If you see the spice powder settled at the bottom, not to worry as it will get dissolved once the brine begins to release.
From the third day on, the mangoes will start to release out the water.
After a week or so, the mangoes will look shrivelled and half the vessel will be filled with the brine.
Continue the shaking process for another week.
By the 2nd week, the 2 kgs mangoes would have shrunk well and will become 1 kg and would have settled at the bottom of the vessel and the brine or the maavadu water will float on top.
Maavadu is ready for use. You can either store it in the same vessel or divide it between smaller jars to facilitate daily use or to distribute to friends and family.
When done and stored properly, maavadu will stay well for over a year at room temperature.