Rinse the chive blossoms in water and spread them out on a clean kitchen towel to dry.
In a small saucepan, warm vinegar over medium low heat to a simmer (not boiling). Turn off heat.
Loosely pack chive blossoms into a clean glass pint jar.
Carefully pour warm vinegar over chive blossoms leaving about a 1-inch space at the top of the jar. Cover the jar and store in a dark, cool location for 3-4 days.
Once the vinegar has infused and turned a lovely shade of purple, strain out the blossoms and store vinegar in a clean glass jar or bottle. Compost the spent chive blossoms.