What items should I use The Void on?

[Ender Engineer]

I read about what it does, but I'm not sure what I should use it on exactly. Should I only use it on active items?

[Nixmachine]

1. Active items - they get absorbed into The Void, and you can absorb as many active items as you like. When you use The Void, all the active items you absorbed will activate. However, one-time use active items (like Pandora's Box) can't be absorbed and used multiple times

2. Passive Items - you can trade the item for stat ups. You will randomly get 2 choices out of 6: Speed Up, Range Up, Tears Up, Shot Speed Up, Damage Up, Luck Up. For example, if you get Breakfast out of a boss room and use The Void instead of picking up the item, you could get +1 Damage Up and +1 Luck Up

[Smetz]

It will also pick up ALL pedestal items in the room, making it great for using on Boss Rush. It's a good idea to remember what passives are given for particular items so you don't use it on something good like damage or tears and get a meh result like movement speed or shot speed.