I am creating a sourdough starter and read to use a "non-airtight" container and store in a warm location for the first 24 hours before beginning the feeding schedule. My issue is that 12 hours in my dough has formed a crust. It is obviously drying out from the open air. How do I prevent this and have it remain "open"? I have it covered with plastic wrap.
You should be stirring ("aerating") your sourdough every twelve hours anyway. If a crust has formed, simply stir it in.
If the crust really bothers you, stir more often, cover partially or use a closed container - it works equally well in my experience.