First, I've used a slow cooker (Crock Pot, the most recent, I think) on the lowest setting (10 h on low) and it is too hot. The liquid boils too hard! The "warm" setting is probably lower, but I assumed it was to keep the food from spoiling and not to actually cook. Then, since I had a very cloudy broth, I tried adding 2 egg whites slightly beaten to the "finger warm" broth and slowly bringing it to a boil, boil it for 10 minutes, then strain it through cheesecloth. Didn't do it.