1. All utensils and jars must be absolutely dry. Dry-roast fenugreek, mustard seeds and urad dahl in a dry skillet until mustard sputters and pops. Cool completely and grind, along with dried red chilies, if using.
2. Juice the 3 reserved limes. Cut off stems of the remaining 9 limes, and then cut into sixths. Mix together turmeric, spices, sugar and salt.
3. If using fresh chilies, cut off stems and chop. Mix all ingredients plus lime juice in slow cooker, and cook uncovered on low setting for 6 hours or until limes are soft.
4. Allow to cool. Pack in absolutely clean and dry airtight jar and refrigerate.
Dry utensils and jars are vital, particularly when making "solar" pickles. Any dampness will spoil the pickle. Remember to wash and dry your limes before starting.
Variation: Both lemon and lime pickle tastes much better made in the sun. In that case, place cut limes and chilies in clean, airtight jar. Pour in spice mixture and lime juice, and mix well. Cover and leave in full sun for 2-3 weeks, shaking the jar daily. Or you can leave the jar in a warm place such as near a heating vent and it will cure. Pickle is done when lime peel is soft.
Source of recipe: I was inspired by several recipes online for traditional lime pickle, most notably http://www.indianfoodrocks.com/2006/05/lemon-pickle-without-oil-picture.... [1]