This is Heston Blumenthal's top tip for making consommé.
It is simple. It works.
You wonder why it's not common practice.
Instead of boiling your pot of stock and then adding egg whites and stuff in a laborious clarifying process, Heston recommends just freezing overnight, then next day (or whenever) thawing in a muslin covered sieve.
The clear consommé drips through and the gelatinous solids stay in the sieve.
He made his consommé a little more chi-chi by adding jasmine flowers, I didn't have any to hand but dropped in a jasmine tisane tea bag for a similar effect.
Even if I say it myself - it was all right :-)