Cleaning involves removing dirt from something, be it a surface, tissue, or individual. It constitutes the most basic level of hygiene and is part of the daily routine of many people. Cleaning involves actions such as removing stains, dusting, shaking, sweeping, and mopping. However, it does not include aspects of disinfection or sterilization, which correspond to deeper levels of hygiene. Generally, cleaning only removes visible or perceptible dirt to the human eye, without considering germs, bacteria, and other tiny microorganisms. 

This is a much deeper process than cleaning and requires the use of products known as "disinfectants," which are usually chemicals and come in solutions, sprays, impregnated towels, or other forms. The cleaning of offices, homes, and other spaces that need to be free of infectious agents may require disinfection. The disinfection process ends with dirt, eliminating viruses, fungi, and certain bacteria along the way, leaving surfaces free of agents that may cause infections to people or animals. 

It is the deepest and most effective level of hygiene, primarily used in hospital spaces and environments that require maximum cleanliness. When sterilizing an object or surface, it is completely free of any microscopic agent, whether harmful or harmless. Usually, homes or work areas do not require this level of hygiene. However, it is a fundamental requirement in health centers, schools, and various companies. An example of sterilization is ozone cleaning. Ozone cleaning has been highly used as an anti-COVID measure as this method eliminates any possible virus in the environment.