Bread-Bakers v103.n033.16

Occasionally I have to deal with a quantity of soured milk. I use what I can in
pancakes, bread or muffins. As the milk sours, I realize it is turning into 
curds
and whey. My question is, if I were to pour it into a cheese cloth covered 
bowl and
allowed it to separate, could I use the the solids or the liquid and what for?

Thanks in advance.
Ken