When glass gets wood stain on it, it is sometimes necessary to remove the stain. Unfortunately, removing the stain can scratch the glass. With careful work, though, the amount of time for you to remove stain successfully shouldn't be more than 1 or 2 hours.
Determine the stain type. Wood stains come in two different bases - oil-based and water-based. It will be important to determine which type because the material used to remove the stain will change. Touch the stain with your finger. Oil-based stain will be sticky to the touch, and water base stain will usually feel flat.
Remove the water-based stain by mixing soap and water together into a gallon bucket. Use TSP cleaner or regular dish detergent at a 2:1 mixture - two parts water to one part cleaner. Apply the cleaning solution with a wash cloth in gentle strokes so as to avoid scratching the glass.
Remove oil-based stains by dampening a cloth with paint thinner. Gently wipe in a circular motion and allow to set for a few minutes.
Scrap any remaining stain with a sharp razor blade. Sometimes small amounts of stain will remain. Gently scrape away any remaining stain with a razor blade. Don't scratch the glass with the razor blade.