Dear GrammyLucie, thanks so much for your answer to Lynn!
I have a broken crock to mend, too (which is how I found this Web site), and your answer got me thinking... so I did a Web search and found that skim milk has a bit more casein per volume of milk (makes sense to me, because the fat is taken out) and no fat that might go rancid. So I think I'll go mix up some powdered non-fat dry milk and boil my crock as you describe. Thanks again!
Mary in LA, February 2011
