The Sony WM-D6C is a large "professional" Walkman produced in the late 1980s. It was designed for individuals looking to record audio on the go, though it is no longer used in the professional world. However, if you have such a device and are looking to use it again, it is possible to repair the hardware so it functions correctly once again.
Open the tape compartment up (press the "Eject" button). This reveals the large cassette compartment. Spray compressed air into the compartment to remove dust that has accumulated in the device. The dust can cause scratches on the tape, preventing it from recording the best possible audio.
Insert the cleaning tape into the tape deck, close the compartment and press "Play." This runs a cleaning liquid through the interior of the deck, cleaning the tape heads and ensuring that there is no dust on the interior of the player.
Wipe down the exterior of the Sony WM-D6C with a damp cloth. Most of the device is leather, and over time this will become stained and dusty. To bring out the original shine, you may want to use a leather conditioner. Rub the conditioner into the leather and allow it to dry (which takes only a few minutes).
Spray additional compressed air into the headphone and microphone connection pots. Debris becomes stuck in these compartments, preventing audio from entering the device or leaving the device. The compressed air forces the content out.