10m Cata Loot - Increase but +1 Drop

I’m trying to think of an elegant way that a 10 man raid could refuse an item and somehow trade/roll it for another one

scenario:

you are in a 10 man and you kill atramedes, he drops a leather helm that you can’t use, a way to sacrifice that item for a % of another raid item or something like that, a 200g abyss crystal is what it currently turns into

so say you got 3 items like this in 1 night, the “bad luck protection” = whatever this system is, allows you to get a good item, or a chance at one