Or, This is what I do (which might or might not take time, since you need to find something to make this work): Find a recipe (i always keep one in my stash), have enough stuff in your stash to fill up your inventory with, open the recipe in your inventory while you also have your stash opened, put the quest item in there. Once you have done that, fill up your inventory with all the junk from your stash. Then close your recipe...bam, your quest item will no longer have space to fill in, and therefore it'll just drop in the ground.