I have tried the "instructions" on the mocrofibre packet, and attacked a VERY greasy oven hob with a dry m/f cloth - and to my surprise, it worked perfectly .
Bit more elbow grease than with a cleaner gunk - but then you dont have to rinse it etc..
If you're a bug freak you can spray it afterwards I suppose, which, being a bug fanatic, you'd do anyway !
But they are designed to be used without any cleaning agent.
And damp on a cloth is all that's necessary for stubborn stuff.
And they're so cheap - 3 or 4 for £1 @ Poundland (that's a surprise price,,) and any will do - you see large "car m'f cloths" - they're all the same stuff.
And they are great as emergency towels for camping - you'd be surprised what you can dry with one ...