In the storage, when for example held down CTRL+D, the items you hover over will be deleted (maybe SHIFT+CTRL+D to make it safer, perhaps an option). When hovering, you can hold CTRL+D and just swipe over items to delete many in one strike. While deleting, items should not change position! Otherwise obviously you're gonna delete everything because all items fly around since items get removed.
If something is unclear, feel free to ask!