Well, it sounds like I'm really late with this, but pour salt water on them and leave them outside to rust some.  Also bang them up a bit and use sandpaper to make sure that any shiny-newness goes away. Also you could use a medicine dropper or turkey baster to drip water down the sides (if you have hard water where you are) so that the calcium remaining behind looks like something that spilled out of the bucket and stained.