I recently installed an old (1920's??) cast iron fire surround. All but the middle section had several layers of paint. The middle section is standard cast iron black. Anyway I've spent a total of 20 hrs (over 3 weeks) stripping the paint from main area of usng all manner of scrappers, chemicals and finally wire wool. I've about 99% of the paint removed, in my ignorance I expected the stripped sections to be black underneath the paint, but its a dull grey/brown. So my question, is there a special paint/wax for getting the thing black.