How hot should a ballast get???

Resistance generates heat. An electric range element operates this way.
I dont know if anyone has put a thermometer on a ballast resistor and knows how hot it would get. I know it was placed where it can catch some air flow.
I saw a post in another forum once where the guy had moved it inside his truck cab. Dangling from the wires maybe. Anyway it blistered the crap out of his fingers.