1. Wash plums and pat dry, cut in half or smaller, and pit. Place in an aging container, pour sugar over, and stir. Add vodka and brandy, stirring to partly dissolve sugar. Cap container and place in a cool, dark place for 2 months, stir occasionally.
2. Place a strainer over a large bowl and strain liqueur. Press the liquid from the plums with the back of a wooden spoon, and discard plum pulp. Re-strain liqueur through cloth until clear, and bottle as desired.
3. Plum liqueur is ready for drinking or cooking, however for best results, age for another month.