I went to our little hospital and selvaged their x-rays. Timing was great because they were throwing them away since the digital machine came in. I took them home and soaked them lightly in clorox and all that black came off. They are great and had no trouble taking the heat. They don't buckle like the mylar that I had---I used them many times over. Those of you who had used the plastic from bacon package, etc. How do they take the heat? I use mine for applique, putting starch on the fabric and ironing the seam around the template shape.