Dull Existing Paint

• 1). Sand the glossy painted finish lightly with very fine, 500-grit sandpaper. Do not use sandpaper with a lower grit, or you will likely carve noticeable scars into the finish. Do not overdo it. Lightly scour the paint until the sheen appears duller.
  
  
• 2). Dampen a soft sponge. Ensure that the sponge is clean and free from trace oils and cleanser residues.
  
  
• 3). Wipe the sanded painted finish with the sponge. Dry the paint with a towel.
  
  

Repaint With Low-sheen Paint

• 1). Abrade the glossy painted finish or the new, less-glossy paint won't adhere. Scour the glossy paint with 100-grit sandpaper until the existing finish feels slightly rough.
  
  
• 2). Place drop cloths beneath the existing glossy finish. Attach painter's masking tape to adjacent surfaces.
  
  
• 3). Apply a particular type of paint based on your personal taste. For a low, muted sheen, apply eggshell or stain paint. For no sheen at all, apply a flat paint. Apply the paint using a roller. Roll vertically while applying gentle pressure. Touch up the surface as needed, using a polyester brush. Let the new finish dry for at least 2 hours.