We learned this technique for cleaning lobster knuckles from Chris Massi. I was more than sceptical when Chris explained the process. I have since eaten my words. And they were delicious. You use an oyster knife to run inside the first joint of the knuckle and pull out the meat. Then you use the knife to break off the shell at the joint. Finally you run the oyster knife inside the second joint and remove the remaining meat. The first few knuckles take some time getting used to. As you get into the groove the knuckle meat seems to fly out of the shells. The process becomes quick and efficient.