Stir to distribute the peel just before pouring into warm sterilised jars (sterilise lids and jars by putting them through the dishwasher and leaving them to dry or washing them in soapy water and placing them upside down in a preheated oven 140C, fan 120C, gas 1 for at least 25 minutes). Screw on the lids (may have to use wax discs if the lids don’t have plastic insides) and label.