Wood stain is a particularly stubborn substance to remove from fabric, as the dye is absorbed quickly by the fibres. There are two types of wood stain --- oil-based and water-based --- and the agent of removal differs for each. For oil-based stains, use white spirit. For water-based stains, use acetone. The following removal method, however, is applicable to both types of stains/solvents.
Take the stained clothing off immediately to begin the removal process. The key to successfully removing any stain is to not give it a chance to set.
Blot the stain gently with a white cloth to remove any excess liquid. Blot from the outer edges of the stain inward to avoid further spreading the stain. Do not rub.
Dip the second white cloth into the white spirit or acetone (depending on the type of stain), then blot the stain with heavy pressure, working from the outside in.
Continue blotting for 2 to 3 minutes.
Wash your clothing as normal. Hang dry. Do not put the garment in the dryer.
Many dry cleaners have special combination solvents that may also help remove wood stain. If the above method does not work, take your garment to your local dry cleaner. In future, always wear clothing you don't care about when staining your furniture and floors.
Acetone can damage clothing. Avoid using it on delicate fabrics. If unsure, test the acetone on a hidden part of the garment.