Place the antique satin dress on top of a white towel. Keep the stains on the satin facing up and out.
Add two to three drops of stain remover safe for satin fabrics to a clean cloth. Blot the stains for several seconds until the stain is well saturated by the damp cloth. Let the stain remover soak for 10 minutes.
Set the washing machine to the delicate or gentle cycle with the coldest water setting available. Add the appropriate amount of liquid laundry detergent -- typically 1/4 cup -- to the detergent receptacle. Pour the detergent directly into the water-filled washer drum if the washing machine does not have a detergent receptacle.
Turn the antique satin dress inside out. Place the antique satin dress in the washing machine and let it run through a complete cycle.
Remove the satin dress from the washing machine immediately after the full cycle. Place the dress on top of a clean and dry cotton towel. Spread the dress out flat.
Start at one end of the towel and gently roll the towel up. The satin dress will be on the inside of the towel. This process gently squeezes excess moisture from the fabric without damaging fibers.
Move the antique satin dress to another dry, white cotton towel and spread the dress out flat. Let the satin dress air dry out of direct sunlight for several hours.