Hi all, came across a large piece of metal which would be ideal to use in constructing an inner door to my fire box (which is too large but don't want to cut it down). It was used to mix cement on back in the day... Problem is it looks like it's been hot dipped in zinc. My question: Given that it's mild steel (low carbon steel) underneath the coating (it looks that way as I've taken a little of it back - the rest looks dull grey-almost black) would it be safe to use after I either got it sand blasted or took it back to bare shiny metal myself. Thanks in anticipation!