1 bottle of gin,
Wash and prick the sloes all over with a fork or something similar. Decant the gin into a convenient jug. Fill the bottle with the sloes and sugar (a funnel is helpful for the sugar) and then pour as much of the gin back into its bottle again as will fill it. Screw on the lid tightly. If there is gin left over, use a screw-top glass jar for any remaining sloes, more sugar and the left-over gin. Screw the lid on well, and turn bottle and jar upside down one day and right side up the next for the next two months. Then once the sugar is all dissolved and the alcohol has taken on a deep red colour, strain the contents through a clean cloth into a bowl, and pour into a jug. Clean the gin bottle of any residue, and pour the sloe gin back into its bottle - or into other clean bottles. Nice idea for presents.