Contraband is any item that should not be in the possession of your prisoners. If a [[Guard]] does find contraband on a prisoner, then a sound will play notifying you of the discovery, followed by a color coded pop-up notification, and finally an item will appear in your to-do list stating how many prisoners are in [[Prisoner#Individual Lockdown|Lockdown]] or [[Solitary]] as punishment. Punishments can be altered if you research the [[Policy]] through [[Bureaucracy#Security|Security]] from [[Bureaucracy]].
Prisoners are not stupid, and will find creative ways to smuggle, steal, and use contraband. New arrivals will almost always carry contraband, some being metallic and others not. So you cannot always rely on your [[Metal Detector]]s to do the job all the time.
A good strategy to use in order to control contraband is to hire some [[Dog Handler]]s with [[Guard Dog]]s to sniff out any smelly contraband your prisoners may be hiding . Another good strategy is to search each new arrival to ensure they are not hiding something. Finally, you can also use the [[Shakedown]] Emergency Action to clean up the whole prison. However, doing this will piss off your prisoners so use it sparingly.
As stated above, new arrivals that are dropped off by a [[Prisoner Bus]] will most likely be carrying something from outside into your prison. However, not all pieces of contraband in the game can be smuggled into your jail. Prisoners will also get their hands on contraband whenever they enter unsecured rooms containing items that can be stolen. An example would be the workshop which holds screwdrivers, saws, drills, and hammers. To secure, simply place metal detectors to the entrances of the workshop. Insecure rooms that contain metallic contraband and are not marked as staff only in the [[Deployment]] screen should also have metal detectors at their entrances.