I use welder's gloves. I shoot a lot of full auto so my cans are hotter than piss. One glove pair I have is good for 1500F, then I switch to my welding glove mittens good for 2000. After that I have these micro chain mail looking covers that go over the mitts so I can go to 2500+.
I usually only need my 1500F gloves.
I have also learned to not shoot my cans (at least in full auto), the last 30 minutes of my range session. They are still hot when I put them away, but not hot enough to cause damage. If I let someone dump a mag, I know I must wait again.
Every round of 5.56 raises the temperature of my M4-96D by 7 degrees. Assuming it's 70deg ambient, my can is 280 degrees after the first mag dump, 490 after the second, 700 after the third and so it goes until I stop or the can blows up. Can's will reach a temperature at which they cool as fast as they heat, but at that temperature of equilibrium, the can's metal is much weakened.