Drain beet juice from the jar, leaving about 1/2 inch juice in the bottom.
Combine sugar, vinegar, salt, and cloves in a saucepan over medium-high heat. Cook, stirring occasionally, until sugar dissolves into a syrup, about 3 minutes. Remove from heat and let cool, 5 to 10 minutes.
Pour syrup over beets in the jar, covering them completely. Seal jar and shake gently.
