Totally weird but I tried it. My broth from the other night was really unappetizingly cloudy and murky. So I did a quick google and learned how to clear it up.
Basically, you beat some egg whites and pour them in the broth, bring to a simmer and the egg cooks and floats to the top grabbing the icky stuff on the way. Let simmer no more than an hour. The resulting UCK on the top can be mostly lifted off, and then I just strained it through a dish towel. Broth is now pretty amber again!
I forgot to check this morning if it's still slightly gelled when cool, but I think it should be. (My first batch was lovely and amber and solid like jello--this batch was murkey and only slightly gelled. I skipped a step or two from what I did the first time, so I'll have to go back to paying closer attention.)
There were all sorts of variations with ground meat and egg-shells...but beat egg whites seemed to be a constant. I just used 2 egg whites and crumbled the shells into the mixture for good measure (worst case, I dump the whole batch!). I don't know if the shells did anything, but the whites cooked up all scummy and skimmed/strained right off. Lovely broth was the result.
I learn something new every day!
(Apparently this is the techinque fancy restaurants do to get crystal clear broths for pretty soup. It does pull out some nutrients probably, but really, the stock was so ugly I wasn't inclined to serve it to ANYONE. This is a better option.)