I was doing a little search on youtube for some casting hints a little while back and was reminded of this video. Using salt and flour, I thought it was interesting. I have not tried it, but after discussion with a friend, thought it may be worth a post here.
It may not be for the high heats, but certainly it may seem useful for pewter or a little higher.... anyone willing to Cast-away and provide some feedback? Obviously, safety precautions are a must and be careful, as the comments say that there are issues with aluminium and salt
there is also a vid on making green casting sand using play sand and cat litter!