The present invention relates to a method for treating, and in particular for abrading surfaces, utilizing glass-like polysaccharide grits. The invention also extends to novel glass-like polysaccharide products, especially starches, and to processes for the production thereof. Additionally, there is disclosed cross-linked polysaccharide materials and glass-like starches having a substantially occluded water component. Combinations of these various polysaccharide grits and other abrasive grit materials are also disclosed.