The edge blackening paint is intended to remain adherent to the glass surface for the life of the filter, without decomposing and/or falling off, provided that the paint on the filter edge is neither abraded by an external agent nor dissolved using a chemical agent such as acetone. Examples of suitable use include being stably secured in an assembly or housing with no exposure to such solvents. Use isopropyl alcohol (IPA) or methanol to clean edge blackened filters, as these solvents don’t affect the edge blackening paint, provided the cleaning is gentle, i.e., not aggressive or of overly long duration. Do not use acetone, as this will remove the paint.