I have discovered that Pine Sol, when used in addition to the regular detergent, is very effective in removing grease and heavy soils from your laundry. Simply rub it full-strength on grease spots or heavily soiled areas before machine-washing. For extra deodorizing power, you can add 1/2 cup to the wash load. Pine Sol should be used only on white or colorfast fabrics. If you're not sure about a particular article of clothing, it's always a good idea to test the fabric in an inconspicuous area first. A small amount really does wonders.
(Taken from the Everyday Cheapskate newsletter)