Waste is right, you just need to put it on the stain for a while - you can even hold some in your hand and rub it on the stain. Ascorbic acid (vitamin C) will immediately lift the stain when it comes in contact with it. You will see a little clean spot where the vitamin c hits the stain if it is a metal stain. You can read through this stains and metals forum to read more about it. Feel free to ask any other questions you have