Thermeal's Pyro-Blok System turns food grade waxed cardboard papers (and other clean post consumer paper sources) into a clean burning cooking and heating fuel.

See their Micro-Plant sized product in action:

Therméal - Conversion of urban waxed cardboard fiber waste to a dense high calorific value solid fuel - Pyro-Blok. Fuel can be assembled from a variety of feedstocks: wet strand cardboard, PCPC milk carton cardboard, brown tissue paper, wood fiber, C&D wood waste, etc. Nike AIR MAX 2090 YOUTH