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Laundry detergent has traditionally been a powdered or solid granular, but the use of liquid laundry detergents has gradually increased over the years, and the popularity of liquid detergent now rivals that of solid detergent. Some brands also manufacture laundry soap in tablets and dissolvable packets, so as to eliminate the need to measure soap for each load of laundry. In some countries where washing clothes by hand is more popular, detergent bars are more popular. Detergent may also be sold in pellets in some brands of laundry ball, although many others do not contain detergent. Soap substitute plants are also used as laundry detergents.
Laundry detergent typically consists of ionic and anionic surfactants which act as the detergent to remove the dirt from the clothes, perfume, phosphors which make clothes appear whiter (it is these that show up under ultraviolet light), and for powders anticaking agents to prevent the powder becoming one large lump in the presence of moisture. For liquid detergents, the bulk of the product is water; for concentrated liquids, somewhat less water, but still the product is mostly water. Biological laundry detergents contain enzymes which act as catalysts to "eat" the dirt off of the laundry; these function best at the kinds of body temperatures found in warm-blooded creatures (30 C (86 F) to 50 C (122 F)) and will perform no better, and sometimes worse, at higher temperatures. Detergents may have other additives such as bleaches and fabric softeners and these are usually advertised clearly on the packets as selling points.
Solid laundry detergent is commonly sold in paperboard cartons, corrugated fiberboard boxes and plastic tubs as a powder, although compressed tablets are also available. In many parts of the world, laundry detergent is also sold in single-use packets or sachets. This single use allows the consumer to buy the detergent they need for the day rather than having to spend a larger amount upfront. The size of the boxes can vary from small single-use boxes sold from vending machines in laundromats to large economy-size boxes. For domestic use, powder detergent is generally sold by volume in box sizes of around 1 kilogram (2.2 lb) and 3 kilograms (6.6 lb). In some cases, plastic measuring scoops have been included inside the boxes.
Liquid detergent is sold in plastic bottles, usually high-density polyethylene or sometimes PET or other kinds. Again, various sizes are available. On large-size bottles, a handle to carry the bottle is often pre-formed as part of the bottle. The bottle caps are often made large enough so they can be used as cups for measuring out the liquid detergent; however this can make the cap very large as the dosage can be as much as 120 millilitres (4.2 imp fl oz; 4.1 US fl oz).
Dosing balls became popular during the 1990s as a way of promoting liquid detergents. The argument was that some percentage of detergent poured into the drawer of the washing machine was lost in the sump. Putting the detergent into a dosing ball that is placed directly onto the clothes would reduce the loss to the drain. These dosing ball devices became more sophisticated, including roller balls, allowing pretreatment. One of the disadvantages of the dosing ball was noise, and some of the more recent examples are coated with softer plastic material.
In addition to the detergent for a washing machine's main wash operation, there are a number of additives such as Vanishor OxyPlus that are added to either the main wash or pre-wash operation. These products claim to improve the performance of standard detergents or to shift stubborn stains.
