[AmityvilleHams]

Sifting would generally be to get out any bugs, pebbles, etc that may be inside the bags when you buy play sand. I'm not too sure on the best possible mesh for sifting, but others may have more ideas on that.

I tend to see 350 degrees Fahrenheit for 15 minutes(sometimes 20-30 minutes) as what people bake their sand at, although time might depend on how thick of a layer of sand you're baking at once.