I keep the empty boxes in the attic, which can get quite hot, so to protect them from possible warping, all extra parts go in a clear plastic sleeve which is kept in a big 3-ring binder. I keep each figures' "extras" in their own individual sleeve. Everything from extra hands to extra jedi robes, for example, which can be easily seen.
The exclusive item or any real cool piece usually goes on the base/stand, at the feet of the respective figure.
The exclusive item or any real cool piece usually goes on the base/stand, at the feet of the respective figure.