Princeton Catalyst Wedges are ergonomically designed to allow you to interact more directly with your medium. This innovative new tool is made from flexible silicone and works great with heavy-bodied paints. It can be used with oils, acrylics, water-miscible oils, and even plaster and clay. Heat-resistant and FDA-approved, the silicone design allows the wedges to be used safely in many mediums, including food crafting. Catalyst Wedges are a godsend for ceramicists: unbelievably easy to clean up and handle, and safe to use with children. The silicone is solvent-resistant and easy to wipe clean with mild soap and water. Catalyst tools are a durable and easy-cleaning substitute for traditional wooden ribs and scrapers.