A scratch in a speaker cabinet is no different than that on a wood floor -- the gouge in the wood is unattractive and impairs the ability to enjoy listening. Eliminate the scratch in the wood by filling it in and buffing the surface using supplies from a hardware store and tools from around the house. Fixing the scratch on the speaker cabinet will restore the attractiveness of the speaker so that you don't turn away from it while listening to your favourite tunes.
Disconnect the wires attached to the speaker -- this will involve pulling speaker wires out of spring-loaded tabs or off of screws, depending on the speaker. Place the speaker on a work surface with the scratch facing up. Spray the speaker with a furniture polish. Wipe the speaker dry with the soft cloth.
Shake the wood stain marker up and down for five seconds. Place the tip of the marker against the cabinet, to one side of the scratch. Press down on the tip as you drag the marker across the scratch. Lift the marker off the cabinet once you reach the other side of the scratch. Repeat this procedure an additional two times.
Inspect the scratch to see if it is now less visible to the eye. If the scratch can still be easily seen, repeat the procedure with the marker. Leave the speaker alone for the amount of time specified in the instructions that come with the marker.
Place a buffing cloth against the cabinet, to one side of where the scratch was. Drag the buffing cloth across the area where the scratch was, using a slow circular motion. Reverse direction once you reach the end of the scratch. Continue to do this for one to two minutes.
Spray the entire cabinet with furniture polish. Wipe the entire cabinet dry with a soft cloth. Return the cabinet to its location before you worked on it and reattach the speaker wires.
Keep all your speakers clean to enhance their appearance.
The wood stain marker should be a neutral colour or match that of the speaker's cabinet or the area that is fixed may not look the same as the rest of the speaker cabinet.