This stuff is amazing!
I can't believe it removed ALL of the black from my woodstove window! I used my woodstove every night from September to mid-April. The first wood I purchased was well seasoned so my window stayed mostly clean. The last load of firewood was supposed to be seasoned but was not and my window kept getting blacker and blacker. Windex was useless. I bought this product hoping to get most of it off and expected to have to scrub it hard. To my delight and amazement, it all came right off! I just put a small amount on a piece of crumbled up newspaper and spread it around the glass, then wiped it dry with another piece of newspaper and it removed ALL the black stain. I am absolutely thrilled! Just rubbed a little harder on the extremely blackened edges of the window,  but it all came off almost effortlessly. I am so happy, I can't stop smiling every time I look at my woodstove now.
Rating: 5 stars