Anybody out there ever try to replace the firepot "Riv Nuts" (thats what they are called in the firepot replacement instructions). These are drop in style thimble nuts that secure the firepot. Want to replace my old ones as they are quite corroded, trying to prevent any future issues. Any ideas would be appreciated. Instruction manual says nothing about how to remove them. Little to no access to hit them out with hammer, but not trying to hhit that hard so i dont screw up the threads. Soaking now with some break free maybe that will help. Replacement Rivs came with a firepot replacement kit...................Any suggestions would be appreciated.