Multiple procedures are presented for removing contaminant material (12) from electron-emissive elements (10) of an electron-emitting device (30). One procedure involves converting the contaminant material into gaseous products (14), typically by operating the electron-emissive elements, that move away from the electron-emissive elements. Another procedure entails converting the contaminant material into further material (16) and removing the further material. An additional procedure involves forming surface coatings (18 or 20) over the electron-emissive elements. The contaminant material is then removed directly from the surface coatings or by removing at least part of each surface coating.