1. Boil one cup of water and stir in four packages of gelatin until dissolved. Remove from heat and add in one cup of cold water.
2. Add about 10 to 20 drops of the fragrance oil to the gelatin. If you would like, add a few drops of food coloring as well.
3. Add one tablespoon of salt to the gelatin mixture to keep mold from growing.
4. Carefully pour the gel into the small jars. Allow the gel to set either at room temperature or in the refrigerator.
5. Set them around your home and smell the fragrance coming from them.
Gel air fresheners are able to scent the air for a long time because gelatin is a polymer. Specifically, the polymer is collagen, a protein that forms a matrix type structure, allowing the gelatin to hold its shape. The fragrance oil particles are suspended in the matrix of the gel which keeps the scent trapped inside. As the gel evaporates, the scent particles are released from the matrix, causing a continuous scent to be released from the air freshener.