Have you never watched Karate Kid.
Wax on ...
Wax off ...
Be careful what you use, it can discolour the casing. Alcohol can eat away some cheap paints and finishes. Be gentle, wet a cloth, ring it out till no drips, dry your hands, then wax on and wax off. A tooth brush is good for all the little nooks and crannies.
If all else fails use the juice of a freshly squeezed lemon, its acidic so you might want to dilute it a bit. Smells fresh too. Lemonade doesn't work.