What is this silver spot on my Dutch Oven?

[timtamtim078]

I just found a Dutch Oven at a thrift store and restored it but I hit a strange issue. I first stripped it for several days in a lye tank, scrubbed it clean, and then seasoned it with Crisco. But after I finished seasoning, a silvery spot appeared on the bottom inside. Since I have restored many cast iron pieces before without this happening, I decided to strip the pot again and repeat the whole seasoning process. But the exact same silvery spot came back in the same location. I have no idea what caused this mark, but I am hoping some of you experienced cast iron restorers have seen this before. And I could really use your thoughts and suggestions on how to fix this.

 

[Alan]

Not sure but it could be lead? Is it a soft spot?

 

[KenH]

My first thought would be to scrape the white spot to see if it would scrape off. If anything does scrape off, what does it seem like - flexible like lead? If you've got a small torch will it melt? If lead it'll melt easy <700°F.

 

[timtamtim078]

It is just flat and smooth. There is no soft spot, either. Do you think it will be removed if I use a rubber brush?

 

[KenH]

Since the lye soak didn't remove the spot I doubt a rubber brush will do anything. OK, I think I understand now - the spot didn't show up after the lye bath, only after seasoning with Crisco? Could it be a small spot that didn't take the seasoning and it's the raw CI showing?

Can you take a photo of the spot? OR, will it show up on a photo?

 

[Dj Jimmy]

You can also use a rubber scraper but do not use a steel brush as it can damage your cast iron.