Wash plums and drain. Let plums completely dry.
Remove any stems including the little stub near the stem.
Discard any plums that are rotten because these can spoil the syrup.
Sanitize the glass jar by rinsing it with boiling water or alcohol.
Layer sugar and plums alternately in the jar.
Cover the jar and leave it in a cool place for 90 days.
After 90 days, remove the plums with the seeds and store the syrup for use.
