They are made from aluminum that has gone through a treatment process that makes them very durable and somewhat nonstick.
Baking sheets not aluminum.
Aluminum oxide pans are the exception to the no aluminum rule.
Also some manufacturers coat their aluminum cookie sheets with substances much worse than aluminum including toxic non stick chemicals which is often done to improve the cooking performance of the stainless steel cookie sheet.
The other problem with stainless steel is that it really is not the best option for conducting heat uniformly and consequently your cookie recipes might not turn out the way you expect.
Our favorite traditional skillet is clad in a non reactive material stainless steel that surrounds an aluminum core for even heating.
Teamfar baking sheet cookie sheet set of 2 pure stainless steel baking pan tray professional non toxic healthy mirror finish rust free easy clean dishwasher safe 4 5 out of 5 stars 884 26 98 26.
Stoneware baking sheets personally i ve not used stoneware bakeware.
The parchment paper can be used in ovens up to 425 degrees.