To make a custom potpourri air freshener, gather some fresh flowers, hang them upside down, and leave the flowers until they are dry. You can obtain flowers that have already been dried as well. Place the dry flowers in a container with an airtight lid, add several drops of essential oils, close the lid, and leave the flowers for several weeks for the oil to absorb. After that, place the potpourri into a bowl or jar.
To make a baking soda air freshener, place the lid of a mason jar on a piece of scrapbooking paper, trace it with a pencil, and cut out the circle. Use a tapestry needle to make holes in the paper circle. Place about 1/2 cup of baking soda in the mason jar, and add eight to 12 drops of essential oil of your choice, adding drops one by one to make sure that the scent isn't too strong. Insert the paper circle into the mason jar ring, and secure it on the jar. Shake the jar several times to mix the ingredients together.
To make a homemade gel air freshener, obtain some heat-proof jars, such as mason jars, and add several drops of coloring and about 30 drops of essential oil of your choice. Pour 1 cup of water in a pot, bring it to a boil, and add four gelatin packets to the pot. Whisk the mixture until the gelatin dissolves, and then mix in 1 cup of cold water and 1 tablespoon of salt. Transfer the mixture to the jars, and leave it to set.