Seriously though, for most exteriors, I recommend a damp microfibre cloth and a very mild detergent/water mix as a starting point. Be careful with older gear. Sometimes fascias are printed with ink that becomes very fragile over time. Solvents other than water, or even just water, can sometimes remove this fragile ink and it’s bloody annoying when it happens.
Wood exteriors can be cleaned with wood soap and then oiled or waxed. I use a special furniture oil for most kinds of wood finishes and beeswax for others. Knobs can be removed and soaked in mild detergent and water mix and then finished with a toothbrush and fresh water. Plastic lenses can be cleaned with mild detergent/water and microfibre, and a little plastic polish can be used where necessary.
Interiors get a little more technical. There are electronic parts and mechanical parts to consider, high voltages and one must be very careful not to damage anything. High-pressure/high-velocity air is a good starting point. I use a cordless blower to loose dust from pieces I work on as the starting point.
Be very careful with turntables. Turntables and cloths don’t mix well, especially not styluses and microfibre cloths. Please don’t ask me how I know or any of the other countless thousands of folks who’ve learned the hard way.
From there it gets more involved, and I recommend booking your equipment for deep cleaning. I use a special deep cleaning regimen I’ve developed and adapted from techniques we use to clean laboratory test and measurement equipment. This involves high-pressure air, cleaners and solvents and a drying oven.
I’m often asked for these details but, given that my process is proprietary, my competitors would simply love to get their hands on it, and that there are risks involved, it’s best that you book equipment in for this type of specialist deep-cleaning.