How do you make a kneaded eraser?

Put the eraser in the freezer for at least 48 hours then take out and let sit for 5 min, put eraser in microwave (make sure to watch at all times) wait until eraser is soft pull out and mold

or you can erase the eraser on a wood table and these strings will start forming. collect the strings and get a eraser ball! let it harden and then eraser!