Cut 10 ripened yellowed limes into eight wedges each. Place in large glass bowl, sprinkle with 2 tablespoons cooking salt and stir well, cover with plastic wrap or lid and leave for 48 hours in cool dark place, stirring occasionally.
Drain, rinse well and mix with raisins and sultanas. Process in batches in food processor until coarsely chopped.
Heat 3 tablespoons peanut oil in large heavy based pan, add cumin, coriander, mustard seeds, chilli powder, black pepper, garlic and ginger (don’t overcook ginger or it will become bitter.).
Cook over medium heat for 2-3 minutes, or until very aromatic.
Add the lime mixture, vinegar and soft brown sugar. Bring to the boil, stirring until the sugar dissolves.
Reduce the heat and simmer for 1½ hours, stirring occasionally. Pour into warm, sterilized jars and seal.
Refrigerate after opening. Makes about 2½ cups (600ml).