Plums can be found from May to August. Choose rich coloured ones ranging from fairly firm to slightly soft. Avoid hard, shriveled, poorly coloured, soft, bruised or split ones. Halve and pit plums and combine in jar with vodka (gin may be used also), sugar syrup, and cinnamon. Cover and invert jar daily until sugar is disolved (about 4 days). Place in a cool dark place for 3 months. Occasionally shake gently. Strain. Ready to serve. Yield: 3 cups plus Container: Wide mouth quart jar