The jellies must be formulated with suitable preservatives such as methyl paraben 0.1–0.2% if intended for long-time use, as the jelling agents used are most likely from natural sources. They must be suitably preserved since all jellies contain large amount of water. Loss of water can quickly lead to scaly form of jellies. Glycerol, propylene glycol, or sorbitol solution may be added. Bases and medicaments that are sensitive to heavy metals are sometimes protected by a chelating agent such as ethylenediaminetetraacetic acid (EDTA).