I would really recommend against painting the radio. Paints may contain chemicals that can be harmful to electronics. Even if you could get the outer shell of the chassis completely removed and separated from the electronics components before painting (which is likely not a small undertaking), the paint can still emit fumes for a long time after drying and those fumes could potentially contain corosive chemicals.
As far as cleaning, most manufacturers recommend thay you simply wipe the outside of the unit off with a damp cloth when cleaning is needed. (NOTE: a damp cloth NOT a wet one.) Most radios are gasketed against dust so the inside of the radio should not require any cleaning. Should the grooves along the outside of radio require extra attention you can use a dry (or damp, if necessary) cotton swab. (Again, not a wet cotton swab.) Do not use cleanser or chemical cleaning products on the radio under any circumstances.
If you have experience in disassembling electronics devices and feel comfortable in your ability to take the unit apart and put it back together, instructions on doing so (including diagrams) are in the manufacturer's service manual which is available from Kenwood Communications. You can contact the manufacturer on their website at http://www.kenwoodusa.com/Communications
. However this should rarely (if ever) be required for cleaning the unit and may void your warranty if you still under the warranty period of the radio.
"Go Ahead. Use Us."