Sponge `Ums are compressed sponge sheets made of high quality long lasting cellulose and are great for all types of painting projects. Use Sponge Sheets by Hygloss when you want great quality, highly resilient craft sponges that you can cut into any shape or object. Craft sponges can be used for sponge painting on walls, making borders, designing t-shirts and more. 4 Sheets; 5” x 7”.