Knead the sweater in the sudsy water for a couple of minutes. Roll the towel and sweater up together, and then fold the whole thing in half. Jump up and down a few times on the towel. In fact, hand-washed clothes turn out cleaner and fresher than if you dry cleaned them. Anything made of cotton can be hand-washed, with little risk of fading or shrinkage.
Metallic fabrics have no problems being carefully hand-washed in cool water.
Dampen your garment, and apply some Lestoil on the stain. Roll the garment into a ball, and leave it somewhere inconspicuous overnight. In the morning, check the progress of the stain. If necessary, use a brush and some laundry detergent to help the stain along. Repeat this process if necessary.