Wool clothing shrinks when it is not washed in the proper manner. Garments that are more than 50 percent wool are likely to shrink when hand washed. Instructions on how to wash a wool garment can be located on the manufacturer's care instructions tag.
Some garments' care instruction labels state that the garment is dry clean only. Other wool or wool-woven garments can be washed by hand in lukewarm water with mild wool-safe detergent. Some aspects to consider when determining how to clean a wool garment are whether the garment is knitted or woven, tight or open, bulky or thin, fuzzy or smooth and if the garment has an inner lining.