The mimeograph "Mimeo" is an outdated printing machine that at the time was the most cost effective way to produce copies of several hundred to several thousand pages. The Mimeo was not capable of photocopying a document. It used wax tissue paper, commonly called stencils. These stencils were placed in a typewriter where the impact of the typewriter key displaced the wax, making the tissue paper permeable to the oil-based ink. The stencil was then wrapped around the drum of the Mimeo machine which was filled with ink. When a blank sheet of paper was drawn between the rotating drum and a pressure roller, the ink was forced out through the marks on the stencil.
A special ball-tipped stylus could be used to cut stencils by hand. However, one had to write carefully, as it was very easy to tear a hole in the tissue paper, resulting in a black blob being printed.
The process was very messy, and ink would often get on one's hands and the pressure roller. In addition, the striking surface of the letters on the typewriter would quickly become clogged with wax.
This information was taken courtesy of:
http://en.wikipedia.org/wiki/Mimeograph