a low cost and an environmentally - friendly synthetic firelog is made by mixing specially processed waxed - cardboard or other wax coated papers of varying proportions with a binder / fuel . the binder / fuel consists of a petroleum wax or a mixture of waxes , the nature and extent of which is suitably modified by in situ admixture with the paraffin wax already present in the waxed - cardboard . sawdust or other wood fillers may also be added . upon thorough incorporation of the materials , the resulting mixture is extruded , molded , compressed , or otherwise formed , such that the resulting mass is sufficiently solid to hold its shape at normal room temperature .