Curse Box
From Super-wiki
John uses Curse Boxes to keep cursed/evil items contained within. The curse boxes were made for him by Bobby Singer and were stored in John's secret storage space in New York. 3.03
The idea for the Curse Box might have come from the legend of Pandora's Box, a box that holds all the evil and all the diseases in the world, until - once opened - it releases all this evil upon the world, leaving only Hope behind.