Stain removal is the process of removing a mark or spot left by one substance on a specific surface like a fabric. A solvent or detergent is generally used to conduct stain removal and many of these are available over the counter.

If a stain has "set", it has become chemically bonded to the material that it has stained and cannot be removed without damaging the material itself. It is therefore important to avoid setting stains that one wants to remove. This can be done by avoiding heat (by not pressing or ironing the stain), sponging stained materials as quickly as possible, using the correct solvent (some solvents will act as catalysts on certain substances and cause the stain to set more quickly), and avoiding rubbing the stain.

Stain removal is possible due to hydrophilic end and hydrophobic end present in detergents. The hydrophilic end of the detergent attaches itself to the water molecules while the hydrophobic end attaches itself to the material and the molecules of the stain. The hydrophilic end allows for the stain molecules to be water soluble. ^{[clarification needed]}

Most stains are removed by dissolving them with a solvent. The solvent to use is dependent on two factors: the agent that is causing the stain, and the material that has been stained. Different solvents will dissolve different stains, and the application of some solvents is limited by the fact that they not only dissolve the stain, but also dissolve the material that is stained as well.

Another factor in stain removal is the fact that stains can sometimes comprise two separate staining agents, which require separate forms of removal. A machine oil stain could also contain traces of metal, for example. Also of concern is the color of the material that is stained. Some stain removal agents will not only dissolve the stain, but will dissolve the dye that is used to color the material.

These are some of the solvents that can be used for stains, with some examples of the stains that they are capable of removing:

Household bleach (e.g., sodium hypochlorite) generally removes a stain's colour, without dissolving the stain itself. Hydrogen peroxide is also a bleaching agent that can be used to treat stains. Sodium perchlorate is a bleach alternative.

Common laundry bleaches include chlorine bleach, usually sodium hypochlorite, and oxygen bleach, commonly sodium percarbonate. Sodium percarbonate releases hydrogen peroxide when dissolved in water, making it a milder oxidizing bleach often used for stain removal and brightening on washable fabrics, while sodium hypochlorite is a stronger oxidizer used for whitening and disinfection but can damage or permanently discolor many colored fabrics.