Gauze sponges are standard medical supplies used in emergency medicine, surgery and ongoing care to clean open wounds and incisions of blood, pus, dead tissue and other foreign material. They generally come in three standard sizes - 2"x2", 3"x3" and 4"x4".
To ensure that portions of the sponge do not stick to or infiltrate the body, they are made of a non-woven material comprised of cotton. They can be provided sterile (for use in surgery or open wounds) or non-sterile (for cleaning unbroken skin).
Sponges used in surgery are often infused with a thread of x-ray opaque material so they can be spotted in the rare event they are left inside a patient.