Things You'll Need
Warped cutting mat
Piece of thick glass
If you accidentally leave your rotary cutting mat in the car on a hot day or absentmindedly run a warm iron over it, you'll be left with a useless, warped cutting mat. But before you discard your warped mat, consider fixing it. In many cases, you can rescue your entire mat, and you can always salvage pieces for smaller projects. You can use any of several approaches to fix a warped cutting mat, as long as they incorporate heat and pressure.
Place your warped cutting mat outdoor on a warm, sunny day. Your mat should rest on an even surface and receive direct sunlight.
Set a piece of thick glass over the warped mat. Make sure the glass covers the entire mat.
Weigh down the glass with a brick (or other heavy object). Place the brick on top of the worst warped area; this will add extra pressure and encourage the mat to flatten.
Allow the weighed-down mat to warm in the sun for a few hours and flatten.
You can also try using an iron to fix a warped cutting mat. Cover the mat with two layers of towels, and set your iron to its lowest heat. Run the iron over the mat, applying extra pressure to the warped area.
If your cutting mat refuses to straighten, cut away the warped area with heavy-duty scissors and save the flat piece for cutting smaller projects.
Fixing a warped cutting mat might affect the accuracy of the mat's grid. Before using a fixed mat for measuring, make sure the grid marks are still correct.