Place desired aromatic vegetables in bottom of buttered heavy pot. Place leftover or reserved bones from filleting (lean fish) on top and cover loosely.
Set over low heat and cook slowly 5 minutes or so until the bones are opaque and some juices are released. Add water or court bouillon, dry white wine, and chosen seasonings and flavorings in a sachet and/or bouquet garni (for easy removal of flavorings and seasonings).
Bring to low simmer, skim as needed, and allow to cook for up to 45 minutes.
Strain and cool properly.