I just got a reversible two-burner lodge logic cast iron grill/griddle. I want to like it because everyone else seems to, but it is leaving brown marks on the white cooktop surface of my electric coil stove, in between the burners. I don't know what the problem is, but the marks are very difficult to clean--the only way I've been able to get them off is with SOS pads, and this is starting to take the white paint off the cooktop. Does anyone know what is causing these marks? Is the heat from the grill/griddle too high for the paint on my stove to handle? Does it have something to do with the oil on the bottom of the grill/griddle? I'd really appreciate the help.