Go to STUFF\TERRAFORM\PROPS\FUNCTIONAL.TXT.
For the treasure chests defined here, comment out the SetFlags and add a price (I'm not sure if the price is required though). It should look something like this:
PropType TreasureChestSmall
{
GadgetName = 'TreasureChestSmall'
GadgetType = #Blowup
BuilderScene = 'BuilderTreasureChests'
Ability = 'MegaItem_CanBePickedUp'
Ability = 'Discoverable'
Ability = 'StudsDiscoveryChestAbility'
SpawnSfx = 'Prop_Spawn'
Price = 250
//SetFlag = #NotUserPlaceable
//SetFlag = #SaveState
}
PropType TreasureChestLarge
{
GadgetName = 'TreasureChestLargeNew'
GadgetType = #Blowup
BuilderScene = 'BuilderTreasureChests'
Ability = 'MegaItem_CanBePickedUp'
Ability = 'Discoverable'
SpawnSfx = 'Prop_Spawn'
Price = 250
//SetFlag = #NotUserPlaceable
//SetFlag = #SaveState
}
PropType TreasureChestLargeNew
{
GadgetName = 'TreasureChestLargeNew'
GadgetType = #Multistate
BuilderScene = 'BuilderTreasureChests'
Ability = 'TestMultiStateAbility'
Ability = 'Discoverable'
SpawnSfx = 'Prop_Spawn'
Price = 250
//SetFlag = #NotUserPlaceable
//SetFlag = #SaveState
}
Next time you see a big or small chest you'll collect it, be able to buy it for 250 studs (or whatever you put), and place them like any other prop. It also won't save that they've been looted, so you can use them over and over again. Chests you've looted before making the change will remain looted, though.
The small chest has an icon, the large one doesn't, but is right next to the small one, so it's still easy to find. I dunno what the difference between TreasureChestLarge and TreasureChestLargeNew is, presumably the new one is the one currently in use.
Edit: See also; unlocking props by default: http://www.rockraidersunited.com/topic/6566-unlocking-props-by-default-unused-props/
Edit: Video.