Nature is full of surprises! I'm building a miniature garden for my wife and just installed some lamps on the front columns. I was wondering how I was going to weather the rust on the concrete..It seems nature took care of my weathering problems over night..Our gutter must have some pecans and pecan leaves stuck in it making a kind of pecan soup..When it rained the over flow spilled onto my garden weathering it over night...Here is a couple of pictures of the rust look under the lamps after the rain.