I've heard they let you choose a specific item effect for an item, but the amount of said effect is random. Now, when you add an item effect to the item.. does that remove the previous effects? Or if you have an item with say..3 Effects, will it just add your effect as a Fourth?

Also if anyone has a screeny on how to use them that would be dandy

Nope, it gives you one specific effect that your looking for with a random Number, then gives you random stats on everything else, as would a brown box.

Ohhh I see, glad I didn't use one then haha that woulda been a ****ty surprise. Thank you!

No problem but it also gives you a chance at getting a max stat on a item lol. So it's always a gamble when you play DBO.