Line a 9x13 pan with parchment paper and set aside.
Melt the sugar, butter, corn syrup, and salt together in a large, heavy-bottomed pot over medium heat. (A stainless steel pot works best for these caramels.)
Once the mixture comes to a boil, add the evaporated milk a little at a time, taking 10-15 minutes per can and stirring constantly. A labor of love indeed.
Once all the milk is added use a candy thermometer and bring the mixture to 238F-240F and not any hotter! Even a few degrees hotter will make them chewy instead of soft. (This will take another 15 minutes or so!) I highly recommend double checking the temperature with an instant read thermometer as it comes to temperature.
Immediately pour into the prepared pan and cool completely. (Once the caramels are cool - I recommend freezing them for 20-30 minutes before slicing. Or you can refrigerate them for a few hours. You don't want them to be frozen solid, but if they're cold this helps the caramels hold their shape when cutting/wrapping.) Cut and serve. Enjoy!