The stacked Spice O’ Life vintage Pyrex casserole stashed in my mother’s cupboard has seen more meals of scalloped potatoes, lasagna, and chicken with wild rice than either of us can count. These trusty dishes have stood the test of time and are now sought-after collectibles. Pyrex clear glassware was introduced by Corning Glass Works (now Corning Inc.) in 1915. At that time, Corning used a special borosilicate glass that resisted the expansion and contraction that occurs during quick, extreme temperature changes. Not only was it exceptional to cook with, the glass was ideal for laboratory glassware and railroad lamps. In the 1930s and ’40s, Corning started using soda-lime glass. The iconic set of four stacking mixing bowls in primary colors (also still in Mom’s kitchen cupboard) came along in 1945. In 1998, Corning divested its consumer products division, forming World Kitchen, LLC, which continued to manufacture Pyrex using soda-lime glass. While a majority of vintage Pyrex pieces can be bought for less than $20, prices can be all over the board. Consider comparing items with an online search. For example, that mixing bowl set of Mom’s sells for $40-$100 on eBay. Look at t...