Eventually every amplifier or hifi component ends up full of dust. There's lots of reasons for this, not least of which the static charge on dust is attracted by the electrical fields around the devices. Dust in general is not conductive and is unlikely to cause shorts, however humidity condensing on the dust when your equipment and the room cools late at night after you have gone to bed can cause problems. The next morning, when you turn on your equipment, there is a much increased risk of shorts across damp dust.
Vacuuming out the dust is about the best the home user can do without opening the cases of the devices. This should not be attempted as amplifiers in particular carry large capacitors which will give an enormous jolt.
If your dust problem gets very bad, a service technician will be needed to clean out the dust before damage occurs.
If you use bare wire connections to your speakers then a regular maintenance program will have you trimming a few cm off each speaker cable to remove the tarnished ends. This will revitalise the sound measurably. Don't forget to do both ends of the speaker cable - the speaker and amplifier ends.
The use of a silver based audio paste to ordinary connectors on the speaker cables as well as the interconnects won't go astray here either.
This should be done every 6-12 months.
Cleaning products are available from Audio Junction for damaged discs as well as the player itself.
Just cleaning your discs isn't enough. The laser lens itself in the player will also build up some degree of road grime, and a cleaning disk with small soft microfibre bristles will perform cleaning duties quite thoroughly.
This cleaning can be done fairly frequently without risk of damage to the laser. But in reality should only be done when required.
Checking all the plugs and connections on the back of the devices to ensure they haven't slipped loos under the drag of their own weight for instance. You can apply a silver based audio paste to these connections to further improve the conductivity of the connection.