Place the blossoms in a bowl of cool water and push them down into the water to rinse them and get all the bugs off.
Drain them and place them into a salad spinner if you have one (if not, place on a clean towel and pat them dry as best you can) and spin them to get the excess water off.
Place the blossoms into a pint size mason jar and then pour the vinegar over them. Place a lid on the jar and store in a dark cool place for a week or two until the flavor is as flavorful as you like.
Recipe by Foods of Our Lives at https://www.foodsofourlives.com/2013/06/chive-blossom-vinegar/