Restoration requires replacing materials in kind whenever possible. The choice was made in this case, however to substitute cast iron for the original brass rosettes mounted on the thin wrought iron cross bars because of the serious corrosion occurring with the coupling of the two dissimilar metals. This approach had the added advantage of naturally distinguishing the old from the new so as not to confuse the historic record. The brass rosettes were never meant to be exposed, especially in an exterior application. The original finish for the whole railing was a black oil base paint. The brass rosettes were removed for cleaning and replaced after treatment of the wrought iron. The water traps seen here were discretely filled with a quality elastic filler material after priming and before painting to insure the longest possible survival of this very delicate detail.