I worked on my veal stock homework over the weekend and was happy with how it turned out as far as flavor, but it was not clear. It had a weird sort of orange-colored film on the top after it cooled. I thought maybe it was fat and tried to skim it, but it was so thin and didn't want to skim off. I also think I probably ruined any chance of having a clear stock because I kept mixing it and checking it and probably should have just left it alone more. I strained it 3 times, twice through a super fine mesh strainer, so there were no bits & pieces of anything.
I couldn't find whole knuckle bones but got a variety of knuckle pieces and shank pieces from a local butcher. Roasted them and added the tomato paste (pic above), then added in the roasted mirepoix & aromatics. Cooked for approximately 12 hours and then did another pull from the bones. I added that batch to the first instead of keeping them for separate sauces. One thing that surprised me was how bad the first batch smelled while cooking, until probably the 8th or so hour. The bones were frozen when I got them and I used them right away, so don't know what that was about, but finally it did start to smell good. I've probably got a gallon+ of stock in the freezer and now just need to find some recipes to use with it.