"Sample" stamps are commonly found on clothing and other items acquired from designer sample sales or from contacts in the clothing industry. Although the articles are perfectly serviceable, leaving the "Sample" stamp in place is unsightly and potentially embarrassing. Fortunately, these stamps are usually ink-based, so alternatively using tried-and-true methods for removing ink stains might eventually prove successful.
Do not put the item in the dryer prior to attempting removal of the stamp. Heat sets stains.
Rub the stamp with rubbing alcohol and a cotton ball. You will probably need to use fresh cotton balls as the stamp is removed.
Try a non-acetone nail polish remover as a more aggressive measure against the stain. Acetone-based removers will damage synthetic fabrics, and may also remove dyes and coloring.
Rub the stamp with a damp abrasive eraser product. These sponge-like items work like extremely fine sandpaper, removing the stamp. Use caution that you don't damage the fiber beneath.
Add a cup of distilled white vinegar to your usual laundry detergent to remove the stamp the rest of the way. Wash the item according to the tag's instructions for water temperature, use of fabric softeners and dryer settings. Ensure the stamp is removed prior to throwing it in the dryer.