Like your car, your ICE also is prone to dust, heat, corrosion, moisure and dirt. Without proper maintenance you would most probably end up with an ICE equipment that refuses to function or worse performs badly.
However unlike your car, you just cant pick up hose pipe and wipe down the dust. ICE is delicate, and is extremely reactive to direct water, its dangerous too.
Here are a few tips on how to clean your ICE;
Generally dust easily catches up with HU. One reason is most HU faceplates are nicely polished and hence attract more dust. Any dust is easily removed with your handy dandy spray can of compressed air, however one can also use use a squeezed wet cloth to clean the Faceplate, Screen area to get those ugly fingerprints going. However the Tricky part is the dust that settle in and around volume knobs and button / Panel crevices. You can use normal ear buds to clean these areas. Alternativley use a soft fabric over a sharpended pencil tip.
Dust buildup over time will affect a speaker's performance, though this applies more to tweeters than woofers. In any case it looks sloppy, so here are two options. Best would be compressed air in a spray can, the same kind used to clean computers and practically every other piece of electronic equipment. The low pressure spurt of air is enough to remove surface accumulation, gently. Too high a pressure, and you could be saying adios to a diaphragm. A normal dust cloth is another option to use on woofers.
Never even attempt to use water based cleaning for Amplifiers; Especially near Heat Sinks, Power Ground Terminals and Output Terminals. The Best option is to use a venerable cotton swab and alcohol (98% Isopropyl), or contact cleaner. Painted amps can be cleaned using a mild cleaner that is sprayed onto a cloth. Under no circumstances spray anything directly onto an amp. The same procedure also applies to raw metal amps, but you can apply a little metal polish to make them sparkle. Finally, if you run bare wire into terminals and it becomes corroded, you can cut off the corrosion and re-strip the wire, but make sure you have enough length to work with before you start hacking away.
Sub woofers dont need any special cleaning. In a sealed Box, The only area where the dust settles will be the Surround and area near it. Normal Dry cloth can be used to clean such Surfaces. Incase of Ported Enclosure, it is advisable to dismantle the sub and clean inner areas every 3-6 months (Depending on usage and dust conditions)
RCA and other connectors
Corrosion, moisture, dirt all of it can be present. Check your RCA connectors atleast once a year. A simple unplugging usually is enough to clean them out, but if they are looking grungy, denatured alcohol (98% Isopropyl) and some cotton swab will do the trick.