The polishing of wood to bring out color and shine and also to protect its surface has been around for centuries, probably starting a few centuries BC. Wood furniture polishes can be broken down into three major categories.
Evaporative polishes are dissolved in an organic solvent that are applied and the solvent evaporates, leaving a thin film of polish behind. Wax is a good example and was the main form of polish used for centuries.
Reactive polishes actually change chemically after they are applied as they dry and cure. Sometimes they react with oxygen in the air. Oil type varnishes are an example of this category. These types of polishes became more prevalent in more recent centuries (17th onwards).
Coalescing polishes don't change chemically but do change in terms of phase (states of matter). Water based finishes are an example.
Current aerosol products on the market like Pledge are generally evaporative type polishes that were introduced in the mid-20th century when aerosol technology became popularized. They are just a convenient way to introduce the polish without having to use a can of liquid and a brush. Most of these aerosol products are not waxes but they do contain silicon that can build up on the surface over time. This is not really a problem with modern furniture but care should be taken with antiques or older furniture with historical value. Aerosol products should not be used as they could adversely affect the value of the furniture. More information should be sought out based on the specific piece and wood type in question.
Early History of Furniture Polishes
Wax and oil forms of furniture polish have been in use since the Iron Age, according to the Canadian Conservation Institute. References dating to the much later biblical times mention using linseed or cedarwood oil to polish wooden surfaces. Since wood has always been heavily used in producing various kinds of tables, bedframes, sofas and chairs, the problem of keeping wooden furniture safe from exposure to drying, cracking and staining elements--like sunlight, cold temperatures, spilled liquids--has always been a relevant concern. Waxes were made into a paste with turpentine while oils were rubbed on as a covering layer.
- biblical era records: linseed and cedarwood oil boiled as a finish and a polish
- twelfth-century Italy: tung seed oil and herbal perilla mint oil, especially for wooden floors
- fourteenth-century France: beeswax for inlaid wood and parquetry floors
- later, beeswax for furniture though it had to be heated and buffed by hand
- eighteenth century (1797): carnauba wax, a natural plant wax from the Brazilian cerara palm, shine with no hand buffing, as required by beeswax
- nineteenth century: discovery of additional natural plant waxes, like ouricui, candelilla, esparto, flax, palm, hemp and raffia waxes
Nineteenth and Twentieth Century Synthetic Furniture Polishes
In the nineteenth century (1800s) petroleum product chemistry began to replace natural wax and oil polishing materials: paraffin waxes, unique for having variable boiling points; solvents, like kerosene and naphtha, to replace turpentine; mineral waxes, like montan wax, extracted through petroleum chemistry from brown coal.
Twentieth century (i.e., 1929) chemistry developed a way to combine the eighteenth century discovery, carnauba wax, with soap and water for the first commercial furniture polishing product--first self-polishing wax emulsion-- though it had the drawback of dissolving easily under water if spilled due to the soap in the formulation. Polymer chemistry by the latter half of the twentieth century had developed synthetic polymer emulsions based on silicon oils, which provided both lubrication (lubricity) and glossy shine. Synthetic polymer polishes are most conveniently delivered by aerosol spray because it can spray the synthetic oils evenly over a large surface area.
Modern Furniture Polishes
Modern forms of polish, which are synthetic, non-natural products of petroleum and polymer chemistry and require high-pressurized delivery into ambient room air, are thought from one point of view to be good because they can reduce work-time and can be manufactured at lower costs without expensive, hard to obtain, limited natural resources (like beeswax, carnauba wax, linseed oil). Modern forms of synthetic polish are thought from another point of view to be bad because they introduce synthetic petroleum-based or polymer-based particles into people's lungs and the indoor-air (polymer: a large molecule called a macromolecule that is composed of many repeated subunits called monomers). The preferred aerosol delivery system is also thought to be bad from this point of view because aerosols contain liquid held under high pressure that is emitted as a spray when increments of pressure are released through the aerosol release valve, which propels various synthetic chemicals, including volatile organic (VOCs) and hydrocarbons, into the atmosphere, usually the atmosphere of a closed room.
Modern Furniture Polishes: Good or Bad?
While the connection between aerosol spray cans and the depletion of the atmospheric ozone layer--found in the stratosphere--resulting from the presence of chlorofluorocarbons (CFCs) in the aerosol, was rectified in the 1970s in America (and many other countries) as a result of voluntary manufacturer action or Environmental Protection Agency law, aerosol still express hydrocarbons and other gasses that contribute to global warming and the resulting global climate change.
While aerosols are now free of CFCs, they still express VOCs that are hazardous to human health (VOC: compound that shares ionic chemical bonds with organic matter such as fatty foods, meats and human skin). When the synthetic chemical nature of modern petroleum-based and synthetic petroleum polymer-based polishes is considered in conjunction with the nature of aerosol sprays, the overriding point of view must be that they are bad for human health since they contribute to short-term (e.g., asthma, migraine) and long term (e.g., auto-immune illness, chemical body burden, polluted indoor air quality) health problems and bad for our biosphere health since they express atmosphere contaminating particles and accelerate global climate change.
Source: "Furniture Polish." How Products are Made. Ed. Stacey L. Blachford. Vol. 4. Gale Cengage, 2002.