I purchased these and hand washed as stated. I placed them on a cookie sheet and made a batch of cookies- While they were baking- my smoke detector went off- there wasn't any smoke that I could "see" but it set it off. When I opened the oven there was some smoke- but I thought perhaps it was some baked over food. The cookies took longer to bake by 2-3minutes. They also had a strange taste to them- sort of like plastic.I later tried using these again- but put breaded fish on them and in a 350deg oven- within minutes of the oven coming to temp. smoke was pouring out of the oven- I had to take the whole pan and food out onto the porch as it was very toxic smelling and smoke everywhere!!I would not recommend these to ANYONE and I am going to try contacting the company with my problem.Hope this review helps.