Attention avid pie bakers--why did commercial bakeries formerly (as in 50+ years ago) use metal pie pans? Were they tin-plated steel, or just steel? These metal pie pans often had the company name and/or logo stamped on them (see photo). What are the performance differences between using a tin-plated steel pan and glass (e.g. Pyrex or similar)? I won't use aluminum, even if the finish is dulled. Eagerly anticipating deep thoughts.