This is a good way of preserving oranges that are too sour to eat - an alternative to Marmalade!

Ingredients
1 Kg sour oranges. thinly sliced or diced. Remove pips as far as possible.
125 g sea salt
3 - 4 heads of garlic pealed and chopped or sliced
3 - 4 red chilli peppers, diced (or equivalent in powder)
150 ml vegetable oil of choice
25 g cumin seeds
25 g mustard seeds  
Any other spices you particularly like!

Method
Heat the first 3 ingredients together and simmer gently for approx 5 minutes.
Place in a glass or ceramic bowl, cover with a cloth and keep in a warm place for 2 - 3 days, stirring 3 - 4 times a day.
After 2 - 3 days fry the remaining spices in the oil, when the mustard seeds begin to pop pour the spiced oil onto the orange mixture & stir well.
Keep covered for another 2-3 days, stirring regularly.
Store in sterilized air tight jars.
Ready to eat immediately, but improves with keeping.
​Serve with curry & rice or chapatti and dhal. 
​(If you prefer a smoother pickle buzz in a food processor before bottling)