Sofa cleaning is performed to remove stains, dirt, and allergens from the Sofa. Common methods include hot water extraction, dry-cleaning, and vacuuming. Hot water extraction, uses equipment that sprays hot water and detergent into the Sofa and extracts it along with any dislodged and dissolved dirt. Many experts recommend hot water extraction as the most effective Sofa cleaning method. Many dry Sofa-cleaning systems rely on specialized machines. These systems are mostly "very low moisture" (VLM) systems, relying on dry compounds complemented by application solutions. Vacuum washing employs a washhead that sprays water without detergent and immediately removes it by suction, creating a swirl of water. This ensures high cleaning performance, extracting the dirt from the Sofa to a depth of half an inch.