Soak sago with one litre of water and curd for 2 hours. Bring remaining water to boil. Add soaked sago to boiling water, stirring constantly. It will thicken and become a paste. Remove from fire. Add lemon juice, green chilli paste, salt and mix well on a plastic sheet or white cotton sheet. Drop spoonsful of batter and pat into round discs. Dry in the sun for two days andpeel off the vadams from the sheet. If cloth is used, it has to be wetted to help peel the vadams. Dry the vadam, one days and store in this. These also have to be deep fried till crisp. The same can be repeated with wheat flour or ragi flour.