G'day. First time poster, hoping the collected wisdom here can help. I recently recovered a J&J Siddons 3 gallon stove pot that we'd used when cooking for shearers in my childhood. It's been in the back of farm sheds, got water in it, used for and to store who-knows-what, and generally abused for 50 odd years, so I stuck it in the electrolysis tank for a bit to get the rust off. When I pulled it out I was surprised to see what looks like the remains of plating on the inside. Does anyone know if Siddons ever plated their pots? The streaks around the inside and marks on the rim seem like soft bright metal. The lid is plated on the inside, but it's not cast. I'm trying to figure out if it's something caused by a previous use (eg. possibly even melting lead), or remains of an original plating. Photo attached.

Could it be the cast it self just polished, On one of my fry pans I used a flapper disk and polished it.

Reminds me of that old paint silver frost. It reminds me of my old grandmothers outside wash basin, which had been painted on the inside to help stop rust.