A strip of felt or a cloth is threaded between several strings. The cloth is placed in the lower half of the strings so that the strings can be played in a regular way.
Cloth in strings.
Felt and cloths mute the resonance of the string. The degree of muting can be influenced by how thick the cloth or felt is and how tightly it is threaded through the strings.
The prepared area should be identified clearly. See: paper notation.