I'm using a new baking pan for the first time. The label says 'commercial-gauge aluminized steel construction used in professional kitchens'. I bought it at Williams-Sonoma in San Francisco two months ago.
So I washed it with soapy water and dried it thoroughly before using. After I greased the pan with a big piece of cold butter, I noticed that the butter I was holding had a grey tinge where it had contact with the pan. The melting butter in the pan's bottom and sides also had a greyish tinge.
Is there any explanation for this? Can it be hazardous?
Thanks in advance!