Solvents are used to dissolve resins, oils, plastics, and grease; to thin paints, varnishes, and lacquers; and to clean brushes, tools, metals, and even hands. By definition, a solvent is a liquid which can dissolve a solid material. Strictly speaking, water is a solvent because it can dissolve solids such as sugar and salt. But the term 'solvent', as it is used in connection with paints and other art materials, means organic solvent . Organic solvents are liquid organic chemicals. These organic chemicals should not be confused with those used in organic gardening or found in natural foods. For example, many of the organic solvents used in art materials can be distilled from petroleum crude oil, and there is nothing particularly healthful or natural about a barrel of crude.