Silazanes and/or polysilazanes are prepared by ammonolysis reaction in liquid anhydrous ammonia by introducing at least one halosilane into the ammonia. In addition to the silazane and/or polysilazane, an ammonolysis by-product also results. A substantially more efficient process is disclosed for treating the by-product through the addition of a liquid, namely water, or a solution comprising a strong base, or an aqueous acid solution. The process may be employed for more efficient, economical recovery of ammonia from such waste stream solutions of ammonia halide, or acids thereof for use as recycle in the further production of silazanes and polysilazanes, and/or for producing a less hazardous, more readily disposable salt residue thereof.