The Basics: MUD’s orange synthetic stipple sponge is best used for special make-up effects. Its coarse and porous texture allows for stippling adhesives, alcohol-based inks and rubber mask grease paint. The large pores are great for creating capillaries, pock marks, bruising, or layering base colors to create realistic skin tones on prosthetic appliances or tattoo cover-ups. This synthetic stipple sponge can also be used to press skin-like textures into oil-based clay prosthetic sculptures.