Another thing you can clean is glass and mirrors. I use a new one on my mirrors at home (rub very lightly), then take a dry cloth over the mirror and there are no streak marks. I think I have tried using it on everything in my house.
I do know that on walls it can leave a 'marking' that can only be viewed in certain light. For me that is better than a black mark that is viewed in all type of light.
DH knows I am obsessed. When I first found it I was buying extra and giving them to my friends because they just had to try it. I have a friend that cleans houses, she tried it on my recommendation and loves them. Last Thanksgiving I couldn't find one to buy...was I upset with company coming over. DH told me that if I would quit telling the world about them then there would be some to buy. He still drove me to several stores before I was able to find a pack that had fallen behind a shelf. Me obsessed...NAH!!!!!!!!!!!! Just don't ask DH.