In natural disasters such as flooding or tornadoes, or simple home maintenance issues such as a pipe busting, oil paintings can take the brunt of the damage. Water damage to oil paintings can leave your canvas looking streaked, splotchy or even moldy. While complete restoration is done by a professional, you can repair your oil paintings at home with some household supplies.
Remove your oil painting from the frame, leaving the stretcher attached to its back. This will allow your painting to air dry and decrease mold growth. Set your painting in a warm, dry place for several hours.
Brush off dried mold and debris from the canvas with a soft paintbrush. Debris and mold can get caught in the paint when you begin restoration.
Dip a clean cloth in lemon juice and blot water stains. Do not rub or wipe at the stains. This will only cause your paint to smear and run, although it is dry.
Wait for your painting to dry for about 2 hours. Place your painting back into its frame and secure the painting, once it is fully dry.