The following shall be observed: The building and all its parts shall be kept in good repair, neat, clean, attractive, and safe. Housekeeping shall meet the highest possible standards of hygiene and cleanliness. All walls, floors, ceilings, windows, and fixtures shall be kept clean. Interior walls and floors shall be of a character to permit frequent and easy cleaning. The facility shall be kept free of unnecessary accumulations of unused furniture, equipment, linen, clothing, and similar items. The facility shall be maintained free of insects, rodents, and harborages, by operation of an active pest-control program, either by use of facility personnel or by contract with a pest-control company. Care shall be exercised in the usage and storage of toxic and flammable insecticides and rodenticides. All outside doors, windows, and other outside openings shall be screened with wire screen or its equal of at least 16 meshes per linear inch.