How To Clean Oil & Grease from Painted Surfaces
Oil and grease can stain painted surfaces as isolated marks as well as unsightly accumulation. There are a few methods you can use to dislodge and remove oil and grease marks, while avoiding damage to the painted surface beneath. As with many other types of stains, treating oil and grease marks promptly will help achieve more successful results. For specialized painted surfaces such as automobiles, refer to the specific articles, techniques and products for those items. Test all cleaning solutions and application techniques in an inconspicuous location before using them in a wider area.
If there is any bulk residue, such as might commonly be the case with an oily, greasy, combination stain, this should be treated first. Removing the bulk residue from the painted surface will help determine whether the stain is still sitting on the surface of the paint, or if it has oxidized and spread deeper into the material. Depending on the size of the area in question, mix a lightly sudsy solution of between 1 quart and 1 gallon of water and a mild pH neutral dish liquid like Dawn or Ivory. Use a sponge to clean the area. Try to avoid over wetting, and allow the painted surface to dry thoroughly. Depending on the material, thorough drying can take up to 24 hours. For particularly tough build-up, a small amount of cleaner containing the active ingredient d-limonene can be added. D-limonene is a grease cutting agent found in many products marketed as citrus cleansers.
Once the painted area has been allowed to dry, there may be an oily or greasy blot remaining. In this case, a poultice can be applied to attempt to attract the grease and alleviate oily marks on the painted surface. Put 1/4 cup of cornstarch in a shallow dish. Add water to the cornstarch 1 TB at a time, until a thick paste is formed. Apply the paste to any oily marks. Allow to dry. Remove and discard the cornstarch/oil poultice. For light colored surfaces, a product like Oxyclean that contains sodium carbonate can be substituted for the cornstarch. This method can have a light bleaching effect, which is why it may not be suitable for darker painted surfaces. The grease and sodium carbonate should saponify, and combine to form a waxy residue that is soluble in water and can be rinsed away.
Follow the application and removal of the poultice with a light overall cleansing using a clean sponge to apply a mild pH neutral dish liquid diluted with water to the affected area. Avoid over wetting, and allow the wall to dry. If a large area was affected, you may wish to use fans to help facilitate drying and prevent lingering moisture that could encourage mildew growth.
Persistent stains that have oxidized (yellowed), occurred on improperly sealed or otherwise compromised painted surfaces may require actual repair involving light sanding and repainting. If this is the case, it is still beneficial to remove as much grease residue as possible and prep the surface for treatment by cleaning and drying thoroughly.
To help prevent future buildup, keep your home well ventilated during activities likely to contribute to oil and grease accumulation, like cooking. Wipe areas down promptly if you notice greasy buildup.
Caution: Never mix cleaning agents or chemicals, the result can be dangerous or deadly. Before cleaning, always test the agent on an inconspicuous location to determine its suitability and to make certain it does not damage the material. Wear appropriate clothing such as gloves and protective eyewear, and work in a well-ventilated area. Accidental inhalation or ingestion of cleaning agents can be hazardous and even fatal, particularly to pets and children.