Originally Posted by
Blizzard
(
Blue Tracker /
Official Forums)
Choosing Your Corruption
In addition to any unlocked Essences, MOTHER will now also offer several new Preserved Contaminants, which allow for a specific Corruption effect (and the associated Corruption penalty) to be applied to a selected item. The inventory of available Preserved Contaminants will change twice each week, mirroring the Assault cadence, and will cycle through all available Corruption effects at various levels of potency.
You can use a Preserved Contaminant to apply the Corruption you purchased to any uncorrupted item that can be Corrupted, much like an enchant.