Determine what caused the stain. Knowing whether the spot on your tux is from red wine or a drop of blood makes it easier to determine how to remove the stain. The majority of stains can be categorized as greasy or non-greasy.
Treat a non-greasy stain, such as blood, with water. Dab a bit of water onto the fabric with a clean towel to remove or significantly lighten the stain. Dabbing is imperative; rubbing sets stains into fabric.
Apply a spot removal treatment to greasy stains such as butter. The solution will help dissolve the stain as it is dabbed into the fabric.
Dab water onto the stain to clean the spot remover off. Do not try this treatment on dry clean-only garments, as applying soap and water could set the stain.
Remove stains by blotting them up. Place a thick napkin or two to three paper towels over the stain and apply pressure to the stain. Replace the napkin when it becomes saturated and continue the process until the stain is gone or no longer transferring to the napkin.