Cleaning Coil and Extrusion Coatings

Coil and Extrusion Coatings don’t get dirty often, as they present a relatively non-adherent, inert surface to airborne soil. If needed, however, a variety of methods for removal of surface deposits are available.

Before beginning to clean coatings, note these precautions:

  • Do not use wire brushes, steel wool, sandpaper, abrasives or other similar cleaning tools, which will mechanically abrade the coating surface.
  • Some of the cleaning agents listed below should be tested in an inconspicuous area before use on a large scale. Always test a small area first.

Hot or Cold Detergent Solutions

A 5 percent solution in water of commonly used commercial and industrial detergents will not have any deleterious effect on a coil or extrusion surface. These solutions should be followed by an adequate rinse of water. Use cloth, sponges or a soft bristle brush for application. Cleaning should be done on the shaded side of the building or, ideally, on a mild, cloudy day.


Most organic solvents are flammable and/or toxic, and must be handled accordingly. Keep away from open flames, sparks and electric motors. Use adequate ventilation, protective clothing and goggles. Remove non-water-soluble deposits (tar, grease, oil paint, graffiti, etc.) from coil and extrusion surfaces using these solvents with caution:

  • Alcohols
    Denatured alcohol (ethanol)
    Isopropyl (rubbing) alcohol
    Methanol (wood alcohol)
  • Petroleum Solvents 
    VM&P naphtha 
    Mineral spirits 
    Turpentine (wood or gum spirits)
  • Aromatic Solvents 
    Xylol (xylene) 
    Toluol (toluene)
    (These solvents should be used with caution on a coil and extrusion surfaces. Limit contact to five minutes. Test a small area first.)
  • Ketones, Esters, Lacquer Thinner Methyl ethyl ketone (MEK) 
    Methyl isobutyl ketone (MIBK) 
    Ethyl acetate (nail polish remover) 
    Lacquer thinner 
    (These solvents should be used with great caution on a coil or extrusion surface. Limit contact to one minute. Test a small area first. Panel manufacturer and coating supplier are not responsible for damage from unrestricted use of these.)
  • Acetone/Paint Remover 
    Do not use acetone or paint remover on coil or extrusion surfaces.

Chemical Solutions

  • Sodium hypochlorite solution (laundry bleach, Clorox)
  • Hydrochloric acid (muriatic acid)
  • Oxalic acid
  • Acetic acid (vinegar)

Hydrochloric acid (10% muriatic acid), diluted with ten volumes of water, may assist in removing rust or alkali mortar stains from coil and extrusion surfaces. Limit contact to five minutes. Caution: Acid solutions are corrosive and toxic. Flush all surfaces with water after use. Oxalic acid solutions or acetic acid (vinegar) may be used for the same purpose. Flush with water after use. Laundry bleach may assist in removing certain stains.

Mildew Removal

Remove mildew with a basic solution of the following:

  • 1/3 cup detergent (Tide, for example)
  • 2/3 cup trisodium phosphate (Soilex, for example)
  • 1 quart sodium hypochloride, 5 percent solution (Clorox, for example)

Rinse with clean water immediately.

Excess Sealant Removal

Precautions should be taken to prevent sealants from getting on the painted surface. Sealants may be very difficult to remove. If any does get on a coil or extrusion surface, it should be removed promptly with a solvent, such as alcohol or a naphtha type. Caution: It may be possible for solvents to extract materials from sealants which could stain the painted surface or could prove harmful to sealants.  Always test a small area first.