Old Stove, I like the bb trick. I never thought of that. I have worked on many old stoves myself, I have a collection of brushes I use, but I'm gonna pick up a pack of BB's and add them to my tool kit.
My suggestion, however, might be to use a commercial oven product for cleaning carbon. I used to do a lot of commercial ovens, and have used a product called Carbon Cleanz or something like that. Zep makes a product called SUPER OVEN BRITE. Bunch of different brands, but they are very strong and corrosive and they work. I don't have any now, but you can get it at a commercial cooking repair place. On an old stove, where the burners are cast iron, you could use this. If you ever do this, don't soak the aluminum heads. DO NOT EVER USE COMMERCIAL CARBON CLEANER ON A DOMESTIC OVEN OR STOVE OF RECENT VINTAGE! It will ruin it. But on an old stove like this, you could remove and soak the cast burners in this stuff . This stuff will remove all carbon believe me. I have used this stuff on some old 40's and 50's stoves to clean burner tubes. But, I use a mask so I don't breathe fumes and very heavy gloves. Might be worth a try if BB's dont work.