If one reads reviews on ceramic glazed cookware (esp. frying pans) one pattern becomes apparent: the pan is awesome at first, nothing sticks to it, even with little to no oil. Then, after a few months the non-stick properties more or less plummet and the pan may become worse than stainless steel pans.

As to why that is, I've read multiple claims. Some say (or assume) that the non-stick layer erodes/dissolves/gets damaged. But to my humble knowledge ceramic is harder than steel, so that seems somewhat simplistic of an explanation. Some sources say that the coating reacts with oil when overheated (which will happen on high settings of the stove) and that residue is what dimishes the non-stickiness.

That sounded more plausible to me and I wondered if that proccess can be reversed/undone in some way?

So the first part of my question: how does a ceramic pan deteriorate? If it's not plain "erosion", what can be done to restore its properties? I'm afraid to scrub if harder for the fear of scrathing it.