Can over whipped egg whites be used in other ways?
It should be easily usable in applications where the egg texture is not that important. Find a recipe which needs both eggs (not whipped) and a liquid, and add the liquid to the overwhipped egg until the foam has subsided. Add the yolks back in (such recipes generally call for whole eggs). 

This should work with different types of griddle cakes: pancakes, waffles, crepes. Also with the liquid used to top moussaka etc., or the liquid used to create straciatella soups.