Carpet that has not been properly maintained may need a deep, restorative cleaning. This is performed through hot water extraction (sometimes called steam cleaning) and may include rotary shampoo cleaning or agitation of the preconditioner with a counter-rotating brush machine.

In order to perform the best job, a technician must follow the “cleaning pie” as taught in the IICRC CCT/CCMT classes. The cleaning pie consists of four parts: time, agitation, chemical, and temperature.

In the shampoo process, a high-foaming detergent is applied to the carpet nap through a shower or channel-feed nylon bristled brush rotating at a speed recommended by the equipment manufacturer that is safe for the carpet being cleaned. A pre-conditioner may or may not be used prior to shampooing.

The agitation of the brush creates the foam that suspends the soil. Depending on the detergent used, either a wet vacuum extracts the suspended soils and detergents, or, upon drying, the suspended soils and detergents are vacuumed. Brushes not properly lubricated with shampoo can cause textural damage to the carpet. 

Rotary shampoo, due to the aggressiveness of the brush, is considered to be a restorative cleaning method. When a carpet needs a true restorative cleaning, rotary shampooing followed by hot water extraction is the method of choice.

Encapsulation cleaning is an interim carpet maintenance method. In this process, the encapsulating chemical is sprayed onto and then brushed into the carpet using a cylindrical or rotary brush machine or bonnet. The encapsulation chemistry surrounds each soil particle and crystallizes it so it can’t attract other soils. The encapsulated soil particles release from the carpet fiber and are removed by normal vacuuming, which will generally be done by the janitorial staff at regularly scheduled times.

Since this is a low-moisture system, carpets can be put back into use promptly. This process allows maintenance companies to provide a continual high level of appearance at a lower price than other cleaning methods while generating high levels of productivity. This method is designed for commercial maintenance only. Encapsulation cleaning should be periodically followed (every 2–3 cleanings) by thorough hot water extraction.

Bonnet cleaning is an interim-maintenance program typically used in commercial cleaning situations. It is considered a low-moisture cleaning system. This process only cleans the face fibers; it does not get the deep down cleaning results from processes such as shampooing and hot water extraction.

Dense foam is produced by a dry foam machine through mechanical aeration of a liquid detergent. A pre-conditioner may or may not be used prior to application of the foam detergent. The foam is distributed and agitated via mechanical brush action. Suspended soil and the foam are extracted by the same machine or with a wet vacuum.

This method is also popular and very safe for upholstery when a chemical designed for upholstery is chosen.