If you're still having trouble, what exactly are you trying to delete? Note that you can only delete an item that's actually in the trash, so if you delete a child item, the parent item will appear in gray in the trash as a context row and won't be deletable (because it's not actually in the trash).
You can, of course, also just right-click on the trash and choose Empty Trash.
Upgrade Storage
If you're still having trouble, what exactly are you trying to delete? Note that you can only delete an item that's actually in the trash, so if you delete a child item, the parent item will appear in gray in the trash as a context row and won't be deletable (because it's not actually in the trash).
You can, of course, also just right-click on the trash and choose Empty Trash.