Very intersting! There is a brief mention of it
here, too - on the 2nd page. It mentions "iron oxide" which I take to mean a very finely divided rouge which used to be called "crocus" - see
this page for details - used for obtaining a mirror-finish.
I can understand the lead lining - soft compared to steel. Crocus is still available, but as it is sold more as a pigment for ceramics it's purity/grit size is a bit questionable, although I suppose a good grind with a mortar and pestle, slaking in water to remove the larger bits and evaporation would produce something usable.
Regards,
Neil