Dry cleaning uses chemical solvents (typically perchloroethylene or newer alternatives like liquid CO₂) instead of water. Required for: silk, cashmere, pure wool, acetate, and garments with internal structure (suit jackets, tailored coats) that would lose shape when wet. Dry cleaning preserves fibre structure and colour but carries environmental and health concerns from solvent residues. Frequency should be minimised — spot-clean where possible.