If using fresh mint, wash it and allow to dry completely. It should then be finely chopped. Peel garlic and grate it. Mix garlic and mint well. Wash and peel carrots.
Drop a layer of carrots in a jar. Pour in the garlic-mint mix and some salt. Repeat until the jar in full. Pour in vinegar to the top of the jar, and place the lid on tightly.
Store in a cool, dry place for 2-3 months. When removing carrots from the jar, use a clean, oil-free spoon or fork.