What kind of stains are usually treated with dry cleaning solvents?

Dry cleaning solvents are specifically formulated to address oily stains due to their ability to dissolve oil-based substances that water cannot effectively remove. These solvents work by breaking down the chemical structure of oils, greases, and waxes found in many stains, making them easier to lift from fabric fibers without relying on water.

In contrast, water-based stains, organic stains, and food stains typically require different cleaning agents or methods for effective removal. Water-based stains are generally best treated with water or water-based cleaners, as they are soluble in water. Organic stains, which may include substances like blood or sweat, often call for specific enzyme-based cleaners that can break down the organic materials rather than solvents. Food stains can vary widely in their composition and may require treatment based on the specific constituents of the food, which is not something dry cleaning solvents are typically designed to handle. Thus, oily stains being the primary candidates for dry cleaning solvents makes this the correct answer.