Wash the maavadu well and let it soak overnight in water.
Next day, drain the water and pat it dry.
The next step is applying gingelly oil so that the maavadus doesn’t turn black. Add the 3 tbsps of oil and mix them well.
Grind the sea salt and mustard seeds together.
Now add turmeric powder, salt - mustard seed mixture, red chili powder to the maavadus.
Mix them well. Make sure all the maavadus are coated nicely with the salt-chilly mixture.
And that's it. Store the maavadus in an airtight container. Make sure you shake them daily. In 3-5 days, you will start noticing the maavadus start oozing out water. It takes at least 3-4 weeks for the maavadus to become tender. More they soak, better they taste. The maavadu water taste equal to maavadus
Mustard seeds act as a preservative.
You can more gingelly oil too.
Instead of red chili powder, you can grind red chilies with salt and mustard seeds.