All types of citrus fruits can be sliced and candied.
Use a mandolin or a knife to slice the fruits into 3mm/⅛in slices. Place them in a large pan and cover with water. Bring the water to the boil, then drain the slices in a colander.
Return the fruit to the pan and cover again with cold water. Bring to the boil, then drain the fruit slices once more. Repeat this process a third time.
Put 2kg/4½lb/10 cups sugar and 2 litres/3½ pints/8 cups water in a clean pan. Bring to a boil over a medium heat, stirring occasionally, to dissolve the sugar.
Add the fruit and lower the heat so that the sugar syrup is at a very low simmer. Simmer for 45 minutes, then turn off the heat. Allow the fruit to cool in the liquid.
Remove the fruit from the syrup and lay it out on a wire rack positioned over some baking parchment to catch the drips. Discard the syrup. Leave to dry for 24 hours.