I'm fortunate enough to have some woodland so I can burn fuel that isn't taxed to death with eco-scam-taxes (apart from property tax). Some people burn dried cow patties, but you have to think ahead and start collecting them in summer so they have time to dry. Farmers won't like you trespassing and stealing their fertilizer, so maybe on crown grazing leases? When the carbon taxes really wind up, then we'll see fights over unlocked garbage bins for plastic fuel to burn. In a couple years at this rate.