To wash heavy blankets in a washing machine, select a mild detergent and a gentle wash cycle with low agitation and warm water. Use a mesh laundry bag to protect delicate blankets. If available, use wool-specific detergent for wool blankets. Avoid using fabric softeners, as they can damage some blanket materials. After washing, tumble dry on low heat if the blanket is suitable or air dry by hanging it on a drying rack. Consider using tennis balls or dryer balls to reduce tangling during tumble drying. Always check the blanket’s care instructions before washing to ensure proper handling.