How to Remove Mold From a Painting

Don't Panic and Follow the Advice of Professional Conservators

Paintbrushes and tools at sink
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 It is an artist's nightmare: an unexpected flood in your home or studio causes damage to your paintings. The water does not even have to touch the artwork, the after effects of mold can do enough damage and, if left untreated, it can spread.

There is hope for your precious paintings, you will want to act swiftly and take care of the problem as soon as possible. You will also need to work smart: know what type of paint and surface you are working with, use as conservative a method as possible to remove the mold, and protect yourself from inhaling any of the mold spores.

The Causes of Moldy Paintings

Mold can grow on any organic surface and your studio need not be affected by a flood for this to occur. Storing paper, canvas, and even hardboard paintings in a dark, damp environment for long periods of time can promote mold growth.

Yet, we hear most often from artists who are trying to salvage paintings after a flood, whether it be a natural disaster or a sewer backup in the basement. Hindsight will often remind us that we should be storing our paintings in the safest room of the house, one that is regulated in temperature and humidity and, hopefully, out of danger from direct water contact should a flood occur.

Anyone who has been in a flood knows that even parts of a building untouched by flood waters can see black mold growth. As hard as you try to protect your paintings, it is not always possible to prevent mold. This means that we need to learn how to remove mold when we see it.

How to Remove Mold From Paintings

Removing mold from any artwork is not an easy task. It's not like you can simply douse it with bleach like you would your bathtub. Art is delicate and making the wrong move can cause even more damage than the mold. Before you begin, you need to do extensive research and look for the least intrusive method of mold removal.

When working with your painting, do so in a well-ventilated area and consider wearing a mask. Mold can quickly be inhaled into your lungs and you also do not want it spreading any further in your home. If possible, work outside.

Tip: When in doubt, particularly with very valuable artwork, seek the advice of a professional conservator. They are trained in working with the most precious of paintings and the cost of their services are worth the final result.

Step 1: Know the type of painting you are dealing with. If it is your own artwork, this will be easy because you know the paint medium and finish you used and are familiar with the painting's surface and many potential reactions. If this is a piece of art you purchased, determine whether it was made with oils, acrylics, or watercolor (they each have distinct characteristics) and whether it is on canvas, paper, or hardboard.

Each type of painting and surface needs to be approached a little differently.

  • Oils are some of the most durable paints though they can have bad reactions with chemicals.
  • Acrylics are water-soluble and can be easily damaged when wet though they may have a protective varnish on them.
  • Watercolor paintings on paper are among the most delicate paintings because it is a water-based paint.

    Step 2: Remove and clean any non-art surfaces as soon as possible. If the painting was covered for storage or displayed in a frame, you will want to remove these items right away. Dampness will promote mold growth and at this point, your painting needs as much air as possible.

    • If your painting was wrapped in plastic (or any other covering) for storage, carefully remove it and throw the cover away (don't take the chance and try to reuse it). 
    • If your painting is framed, disassemble the frame and remove the painting. Clean the glass and frame with a 10% bleach solution (1 cup bleach to 1 gallon distilled water). Do a test on a small, inconspicuous part of the frame to ensure you do not damage the finish.
    • If your painting is stretched on canvas, check all parts of the stretcher frame and clean them with the alcohol solution mentioned below and take great care to not get the canvas itself wet.

      Step 3: Do conservative cleaning of the painting itself. The approach you take will be determined by the type of painting you have and it is best to begin with the method that has the least potential for damage. Do not attempt to clean the painting without weighing all of your options.

      It is best to look at the advice of expert conservators who deal with these issues all of the time. Here are some trusted resources you should look at:

      Do not take just any advice from the internet (especially public forums) and if you do, be cautious. There is a lot of bad advice out there and while it may have worked for someone else, it may not have been the best solution for the long-term. For instance, some advice suggests a watered-down vinegar cleaning solution, but you must remember that vinegar is 5-8% acid, which is not good for paintings.

      The goal with cleaning the painting is:

      • Remove as much mold as possible.
      • Do this without damaging the paint or the surface it is on.
      • Prevent the mold from growing back.
      • Protect yourself (and your family) from harmful mold spores.

      Very Important! Do not wipe any mold off of the painting as it can smear and stain the piece (even on a blank part of the canvas or paper). Conservators can remove mold, but these stains are almost impossible to clean up.

      The resources listed above suggest many approaches to removing mold from paintings. Here are a few of those suggestions in brief (be sure to follow the links above for details and more advice).

      On the back of the painting: It is preferred to attempt mildew removal from the back of the surface so you do not damage the paint. You do not want to saturate a canvas, but lightly mist it with one of these to stop mold growth:

      • Lysol (a brand of anti-germ/bacteria cleaner - the spray and not the liquid form) is recommended by the New Orleans Conservation Guild.
      • Commercial rubbing alcohol (70% alcohol) mixed with water in a fine mist spray bottle is recommended by MOMA.

      On the front of the painting: Obviously, the front is the most critical surface of a painting and it is best to avoid working with it if possible. If you must, it may be best to allow the mold to dry before removal.

      • MOMA does suggest that a cotton swab lightly dampened with a mixture of 70% alcohol and water can be dabbed onto small clusters of mold. However, this can damage the paint and should be carefully tested prior to any attempts.
      • Dry mold can be brushed away with a soft bristled brush. MOMA recommends doing this with a HEPA filtered vacuum hose next to the painting to suck up any mold dust.

      Drying the painting: Yes, we have all been told that sunlight damages artwork, but in this case, you will use it to combat mold. The time that a painting sits in direct sunlight to dry (initially or after any of the cleaning attempts described) is not long enough to damage the paint color.

      • Set a damp or wet painting in direct sunlight for 2-3 days or until it has dried completely.
      • For fast drying of wet paintings, do so outside (if possible) by placing the painting on a towel, blanket, or board in the sun to dry.
      • For indoor drying, place the painting as flat as possible in front of a sunny window.

      A Final Word of Advice

      Remember to work quickly but also be smart about every move you make with a moldy painting. You do not want to rush into cleaning a painting just while you are in a moment of panic. Take a deep breath and formulate a plan of attack for your mold problem.