Question about Kanga XXL Choice Cloth - 117368

I don't know the problem now, I just clean the dust off with the hoover with an "open" nozzle. Are they lines in the sense of discolouration or simply a different light reflection due to the pressure point?

You have to turn the bottle upside down and close the cap too!

and what can I do about it or how can I get rid of it.
Do I have to put it in the washing machine? How warm?