When dusting and dry cleaning methods do not remove dirt and grime from varnished or unvarnished paint surfaces, than an aqueous cleaning method may be used as an alternative. Aqueous cleaning methods are more invasive than dusting and dry cleaning, so caution should be exercised when using these methods. Studies show that oil paint films are sensitive to water especially where the paint has been used to create a great range of surface effects (Tempest 2010). Aqueous foams and gels are currently used in conservation practice as an alternative to simply using water on paint surfaces (Heckenbücker 2010; Wolbers 2000; Stulik 2004).
Spit Cleaning Method
Using spit to clean a painting may seem absurd, but it’s a method used by professional conservators. Saliva has enzymes (α-amylase has been identified as a key cleaning agent—Romao 1990) and chelating compounds that can help to remove dirt and grime, but that will not damage paint.
For this procedure you will need cotton-tipped applicators or cotton balls.
- Lightly wet the swab with your spit. Don’t soak the cotton, but wet enough to pick up any dirt particles with ease.
- Gently dab the wet cotton over the painting. Don’t move the cotton from side to side, but instead up and down in small, soft dotting motions. Work a square inch at a time.
- Wet the other end of the swab. Once the swab has picked much dirt it is no longer useful, discard the swab and wet a new one.
- Keep a glass of water handy. You should be working slowly enough that you don’t feel like you’re running out of saliva. Just in case your mouth does start to get dry, though, take a sip of water and wait a minute or two before going back for more spit.
Mini Picture Cleaning Kit with Picture CleanGel—an aqueous cleaning gel—contains all materials needed for dry and aqueous cleaning.
Water and solvents are effective for removing dirt from picture surfaces, but they also penetrate the surface and potentially damage the layers of paint. Gels are able to reduce the penetration of cleaning solutions into paint layers and reduce mechanical stress to the surface during the cleaning process.
Another important consideration in aqueous cleaning materials is to reduce the amount of components such as solvents, surfactants and other cleaning compounds that may potentially damage paint surfaces, but also leave residues that can affect paint. Most household cleaning products (e.g., Windex) contain large amounts of surfactants, alcohol, ammonia and other ingredients that can irreparably damage paint surfaces and leave residues that promote poor adhesion of subsequent paint layers or varnishes.
Picture CleanGel is a solvent-free aqueous gel cleanser designed to remove soil from varnished or unvarnished paint surfaces.
Picture CleanGel made by Natural Pigments is a solvent-free aqueous gel cleanser that is gentle to both varnished or unvarnished paint surfaces. Picture CleanGel is composed of ultrapure deionized water with a low concentration of surfactants and chelating agents. The gel cleanser is designed to remove soil, proteinaceous (e.g., collagen glue) and carbohydrate (e.g., gums) materials from varnished and unvarnished oil paint surfaces. It is also useful as a cleaner for unvarnished oil paintings that have collected dirt and dust prior to varnishing.
Read the directions carefully and proceed to use the product only according to these directions:
1. Pump a small amount of Picture CleanGel onto a soft-haired flat brush.
2. Apply the gel and stir momentarily on the surface with the brush.
3. Wipe away almost immediately with a dry cotton swab or cotton ball and allow to completely dry. Roll the cotton swab on the surface to avoid abrading the surface of the painting.
4. Rinse with deionized water and allow to evaporate to dryness. Moisten the cotton swab or ball with the deionized water and gently wipe the surface by rolling the cotton on the surface.
5. Rinse with mineral spirits in the same manner as the deionized water and allow to evaporate to dryness.
CAUTION: Use the products in the Mini Picture Cleaning Kit only as directed. Test all products first on an inconspicuous part of the painting before using it as directed. Use sparingly and only on dried oil paint or varnished surfaces. DO NOT USE ON ACRYLIC PAINT. When using water and mineral spirits to remove the residue from Picture CleanGel, test first on an inconspicuous area of the paint surface. On new oil paint surfaces, the mineral spirits may cause lifting of pigment or paint. If this happens, use only deionized water to remove Picture CleanGel residue from the surface.
Heckenbücker, Anne and Demuth, Petra (2010) “Extended Abstract—Surface Cleaning with Aqueous Foams”, New Insights into the Cleaning of Paintings: Proceedings from the Cleaning 2010 International Conference, Marion F. Mecklenburg, A. Elena Charola, and Robert J. Koestler, Editors, Universidad Politécnica de Valencia and Museum Conservation Institute, 2013, pp. 225–228.
Romao, Paula M.S., Alarcao, Adilia M., Viana, Cesar, A. N. (1990) “Human saliva as a cleaning agent for dirty surfaces.” Studies in Conservation, Volume 35, pp. 153–155.
Stulik, Dusan (2004) Solvent Gels for the Cleaning of Works of Art: The Residue Question, Dusan Stulik, V. Dorge, Editors, Getty Publications, 2004.
Tempest, Hannah; Burnstock, Aviva; Saltmarsh, Polly and van den Berg, Klaas Jan (2010) “Sensitivity of Oil Paint Surfaces to Aqueous and Other Solvents”, New Insights into the Cleaning of Paintings: Proceedings from the Cleaning 2010 International Conference, Marion F. Mecklenburg, A. Elena Charola, and Robert J. Koestler, Editors, Universidad Politécnica de Valencia and Museum Conservation Institute, 2013, pp. 107–114.
Wolbers, Richard (2000) Cleaning Painted Surfaces: Aqueous Methods, Archetype Publications, 2000.