Hi Bluberi, I had this problem too... But later i use Pledge (Lemon, yeollow can) to polish the top and it become shine shine again. Now i will polish the top once a week. I also found that hot things, magazines, letters, put on it for too long also will cos the stain. and the contactor told me that the surface must keep dry at all time,cos if water gets into it, it will also cos the stain.. Hope this infor helps you.