Hi all. I dont clean the glass as often as i should and hence it has developed tough to clean stains on the glass. Stains are dark brown/black and wont come off with damp paper towels which is what I normally use to clean the glass with. Other times i use glass cleaner to really clean it maybe every other month. The stains it has developed only seem to come off if i scrape it with a fingernail. Can i use a scotchbrite pad to clean it with soap and water? Will that damage the glass? Thanks.