Thrifted Griswald is contaminated with lead :(

Holy shot never thought to test used cast iron of unknown provenance.

You can def strip it, the lead contamination is in the seasoning but it’s not gonna get into the iron. Buuuut sanding that down will be a hazmat zone. I’d bunny suit/sealed goggles/P100/sand on plastic sheet cause that’s gonna be the worst case for lead dust. Idk if it’s worth it.

Check flurospec if you have some extra disposable cash for better lead tests https://www.detectlead.com/, I wonder if the types of tests you used turned red due to interacting with iron or something (unlikely but possible, they incorrectly react sometimes and it’s red so monk brain wonders…)