What I do is putting a very short spray of Glassex or any window cleaner on a piece of cloth. With that damped cloth I wipe my CDJs/mixer or whatever I want to clean. Never spray cleaner solution directly on your equipment though, it might leak into the housing...
I've made my own cleaner by putting a few drops of green soap, some spiritus (don't know english word) and 95% water in a container with a spray. It cleans all grease but is not aggressive.