Credit: Audrey Patsiga / Getty ImagesKey PointsEstate sales, small thrift stores, vintage shops, and online platforms often have the best Pyrex. Look for primary-color nesting bowls, rare patterns, and older pieces with all-caps stamps.Pyrex is prized for its rarity, history, and nostalgic family connection.If you’re an avid secondhand shopper and/or cooking enthusiast, you’ve likely come across vintage Pyrex at some point. Perhaps you’ve wonder…