In a partially finished electron-emitting device having electron-emissive elements (56A) formed at least partially with electrically non-insulating emitter material, electron-emissive element contamination that could result from passage of contaminant material through an excess layer (56B) of the emitter material is inhibited by forming a protective layer (58 or 70) over the excess emitter-material layer before performing additional processing operations on the electron-emitting device. Subsequent to these processing operations, material of the excess and protective layers overlying the electron-emissive elements is removed to expose the electron-emissive elements.