Did you know that I've been in the residential cleaning business since 1998 and we have never cleaned 1 wall? I know there are lots of people that do but it just doesn't seem like something I ever wanted to get in to.
Magic Erasers were originally meant to clean things such as walls, light switches, doors etc. Back in another life of mine there used to be a guy from Procter & Gamble that we associated with. This was when Magics first came out. I was having problems with a ring in a bath tub that we couldn't get out and this lady was raising all kinds of hell about it. Anyway, my buddy in Maryland (professional commercial cleaner) suggested that I try the Magic... so I did. It did work so I told the guy from P & G about it. So then it took me 2 years to perfect how to use it for wet work.... the Magic was originally packaged for dry work. So I'd give the P & G guy updates and finally only after several years did they add how you can clean showers etc on the box.
And there you have the history of the Magic Eraser..... well, the latter history of it. It's original use was to sound proof rooms.