Optimist Mixable Color is waterproof, so it can be tricky to remove from surfaces and brushes if it dries. That's why we created Optimist Ink Solvent, a gentle solvent that breaks the chemical bonds in wet or dry shellac. Squeeze Optimist Ink Solvent onto your palette and brushes after a painting session, and our shellac-based ink will quickly start to break up and peel away. Rinse brushes after using Ink Solvent for best results. Optimist Ink Solvent is packaged in a 200 mL Precision Bottle. Squeeze the bottle to dispense a controlled flow.