Pick and wash a colander full of fresh leaves of spearmint, lemon balm, and lemon verbena and triple rinse in a big pot. Inspect to make sure it's clean. Strip leaves off lemon verbena plant. Chop mint and lemon balm. Boil about 2 quarts of filtered or spring water. Add in herbs, stirring for several minutes. Turn off heat and let sit covered for 5 minutes. Pour tea through a sieve and at least 4 layers of cheesecloth so finished product is clear. This is a concentrate that will be diluted 2 to 4 times according to your individual taste preferences. Will stay fresh for 4 to 5 days if kept refrigerated. Serve over ice with or without sweetener.