As a regular user of Mechanix M-Pact II glove who handles hot exhaust and welding, not all Mechanix gloves will melt. Exhaust is significantly hotter than a 'hot canteen cup'. Using standard leather work gloves provides no insulation. You may be able to quickly brush against exhaust pipe, but anything more and you'll be burned. Flight gloves usually have thin leather palms/fingers. Some protection, but not much when work gloves are needed. VoE.
Spandex has a melting point of about 450° F, and Jetboil sees fit to surround their highly conductive titanium alloy cook pots with spandex sleeves.