Sodium Bisulphate

In the textiles industry, it is sometimes applied to velvet cloth made with a silk backing and a pile of cellulose-based fiber (rayon, cotton, hemp, etc.) to create "burnout velvet": the sodium bisulfate, when applied to such a fabric and heated, causes the cellulose-based fibers to become brittle and flake away, leaving burned-out areas in the finished material, usually in attractive patterns.