Black Fax
Fax machines are a useful and versitile addition to almost any business. if you have one you are probably faxing out leaflets and press releases or even using the fax on demand function for the distribution of a few page long newsletter. the loss of your machine may or may not hurt that much, but many businesses rely heavily on the constant good working order of their fax machine.
The easiest way to destroy this good working order is to send a solid black sheet of paper as many times as possible. wrap the black paper around the roller of your fax machine and let it keep transmitting. the fax at the other end will burn out the thermal head, in some cases even starting a fire if the paper becomes jammed and it doesn’t shut itself off.
if you want them to know why this happened to their fax machine you could print in small white letters a breif explanation, i.e. “stop destroying the rainforest” but this is unneccesary and if you or your group have been involved in actions against them for that reason you will automatically be considered a suspect.