Likely environmental contamination - iron in the environment or more likely contamination from other cars at the car wash. https://www.stainlessfoundry.com/meta

Likely environmental contamination - iron in the environment or more likely contamination from other cars at the car wash. https://www.stainlessfoundry.com/metallurgy/knowledgebase/iron-residue-contamination/ https://www.stainlessfoundry.com/metallurgy/knowledgebase/ir...