Lekue 12 by 16-Inch Silicone Baking Mat, Clear All lekue baking molds are made of platinum silicone and can go in the oven or microwave; platinum silicone molds are treated with special nonstick so only need to oil them before first use to activate the nonstick properties Fiberglass baking mat covered with liquid platinum silicone; the structure of the mat (silicone and fiberglass) allows for optimum distribution of heat and uniform cooking in a shorter time It is a cooking utensil, not simply a baking sheet liner Use in the oven or as a work surface Folds to store; dishwasher safe