Circulon Wok Cooking Residue On A Wok?

Cooking residue on a wok? - circulon wok

I have a Circulon Wok hand with a friend who was until recently, I realized that black residue left on parts of the wok. If the zero from the outset as their black flakes. It is never possible to eliminate all the black spots, the catches of new products, like every time you cook. I do not think it is the non-stick Teflon-covered, the inner surface of the wok is placed a little too hard with them in harmony. But I fear that the residues of burnt food. Is this serious?