@werehatrack At around 176F (80 °C), a magnet will lose its magnetic force and it will become demagnetized permanently if exposed to this temperature for a period, or if heated above its Curie temperature.
Plastics ha a wide range of temps to melt. From 160-600F
I own a pair. I don’t grill, but they are nice little spotlights on a gooseneck.
During our last power outage I learned the value of flashlights that can stick to the refrigerator and light up the gas stovetop. These are better lights that are easy to aim with a much more robust magnet.
I have also used one as a work light when I needed to shine a light down a drain.
If you pull out the battery holder there is more than enough space for a cylindrical lithium battery larger than 18650.