Store the aloe gel in the refrigerator in a plastic container that is safe for food storage or a glass container. The best container choice is a dark green or brown glass jar, which helps to keep out light. Many people add a drop of vitamin E and a small amount of citric acid powder to prevent discoloration and make the aloe vera gel last longer. In place of citric acid powder, simply crush a vitamin C tablet into powder or use a drop of grapefruit seed extract.