The basics White Collar Grime: adhesive shirt collar & hat protectors. The pro tip Prevent hat sweat stains and protect your favorite headgear. The uses A shirt collar protector or collar protector to prevent ring around the collar stains, tames tags, and cover up itchy embroidery, making shirts so much more comfortable to wear. The bottom line No ring around the collar stain, no hat sweat stains, no nonsense.