They don't do anything but sit there and rot, going down every turn. In our MP game, we have a script that can get rid of them (see below). The script example takes prisoners from Britain and America, and gives them conscripts and officers back (the conscripts returned would be from their prisoners held by other countries). You will need to load each countries turn to determine how many prisoners they each have. The script fires 4 times, and occurs every 2 turns (that's what the turn index does). To use, take the number of prisoners and divide by 100, this is the total number of prisoner points to return. Take that number and divide by 4 to get the value. So in the script below, on the F10 screen, Britain had 29,600 German prisoners to start. You divide that by 100, and get 296 points (divided by 4 gives you 74 points to return each turn). Someone had 354,000 British prisoners that will go free now, and re-join the British pool. The officers are 10% (rounded down) of the conscripts returned each time.
If you don't want to return the prisoners, remove the ChangeResStock lines and you will simply remove the prisoners. You do need to know the faction tag for each group of prisoners you have (the F10 screen shows flags and not faction tags).
SelectFaction = $CMN
SelectRegion = $Oesterreich
StartEvent = 1870 Return of PoWs from the Wars Involving NGF-France-Britain-US-China-Rus |4|1|NULL|NULL|NULL|NULL
Conditions
TurnIndex = 0;2;4;6;8;10;12;14;16;18;20
Actions
SelectFaction = $GBR
ChgPrisoners = $GER ; -74
ChgPrisoners = $RUS ; -2
ChgPrisoners = $CHI ; -4
ChangeResStock = $merConscript;887
ChangeResStock = $merOfficer;88
SelectFaction = $USA
ChgPrisoners = $GER ; -44
ChgPrisoners = $RUS ; -5
ChgPrisoners = $CHI ; -76
ChgPrisoners = $CSA ; -46
ChangeResStock = $merConscript;79
ChangeResStock = $merOfficer;7
EndEvent
Remember - The beatings will continue until morale improves.
[SIGPIC][/SIGPIC]