THE RESULTS OF THE LATEST HEAT TEST!
I ran my own test yesterday. We had 105 temps and so I put various M&M's packages on the dash of my car in front of the reflector (more heat) and closed the car up to see how everything would fare. I tested regular M&M's, peanut, dark chocolate peanut, and mini's in the plasic "tube"- "pop and share". When I checked on them later they were all still "rattling" in their packages. That meant that although the chocolate may have softened. as long as the candy shell remained intact it kept it from becoming a melted blob.
I would think, though, that if you decide to put them in a package you wrap the package of M&M's in a layer or small bubble wrap after putting in a zip lock bag in case of shifting or box damage. Any squishing of the box & M&M;s at high temps would still mean a chocolate mess---that someone would have to lick off the box!
Debbie -- (Proud grandaughter of WWI Army LT sharp shooter, and daughter of WWII & Viet Nam "Victory Ship" veteran)
"...To know that even one life has breathed easier because you have lived, that is to have succeeded." --Ralph Waldo Emerson