Grill cloth is the fabric material on the front of your guitar amplifier that protects and conceals the face of your speakers inside the speaker cabinet. While rips in your Marshall amp's grill cloth are mainly a cosmetic problem, major tears in the cloth can leave your speakers open to moisture and physical damage. Fortunately, most speaker grills can be removed and replaced by the average guitar player.
Turn off your Marshall amp, and unplug its power cable. If the amp has a separate speaker cabinet, relocate the amp head to a separate location.
Remove the grill cloth frame from the amplifier. This is the wood framing where the cloth is attached. In most Marshall amplifiers there is a ring pull that allows you to pull the cloth frame from the speaker cabinet assembly. Relocate the grill cloth to a large, flat work surface, and place it facing downward.
Use a heavy-duty staple remover to pry off the staples securing the grill cloth to the wooden frame. Remove the cloth material from the frame, and set it aside.
Spread out the grill cloth material on your work surface. Place the wooden grill frame on top of the cloth material. Use a pair of sewing or fabric scissors to cut the fabric down to size so it fits along the wooden frame.
Line one edge of the cut grill cloth material along one side of the grill cloth frame. Position the cloth so its cut edge is perfectly aligned with the inside edge of the wood on the frame. Use a staple gun to attach the section of cloth to the wood frame. The staples should be about one to two inches apart. Repeat this to attach each section of grill cloth to the wooden frame.
Place the grill cloth frame back inside the front of the speaker cabinet.