Thanks every one for the help.

??? Back in the old days, we used to wipe them down with waxed paper: old bread loaf wrappers worked very well, they weren't plastic in those days, they were paper, waxed.

You must be psychic.

Black ceramic or black iron?

If the latter please to treat like a cast iron skillet. If the former please to read onward.

Usually the biggest problem is grease - you need to use a degreaser to kill the grease and get it off. Then the next problem (caused by decreasing) is that you leave a film. For that you need a bottle of vinegar and water, 1:1 ratio works best. Spray a little bit and wipe and buff - the residue "stuff" will come off leaving a sparkling shine.