Hoping that some high heat "BBQ" paint will suffice. Don't know what else would survive the heat. Nobody will care if there's a little black color around the legs of the one I'll repair. Regardless, I've got to slather some J-B Weld Extreme on there after the rust removal, or the protective coat won't matter.
I used stove paint on one of mine and it held off the rust for years. The one I am working on now, green, will get black high heat grill paint around the leg sockets after some JB Weld Extreme. I'm dealing with the same thing as you, legs still attached but a little bit loose. Mine is getting an ash bucket so no one will ever notice the black paint.
Today I flipped it over and presoaked with PB Blaster, where the legs go into the sockets.
The legs won't budge, and I need to remove all of that of course in order to properly soak the sockets with Evapo. Wish me luck in not twisting off the sockets, since some of the welds have already broken from heat and age!
I think I'll have to put Vise Grips on the sockets to keep them from spinning and another Vise Grip on the leg while twisting ... but I'm about ready to just cut the legs off and then methodically work them out of the sockets by squeezing them with the Grips or something. One of the sockets appears "split," I'll have to probably squeeze it with Grips while some J-B takes hold there.