Has anyone heard of using chalk for gumpaste flowers? If so how is this used?

I remember reading reading a post on this a while ago. I remember when I first started making gumpaste flowers that the directions said to use a non-toxic chalk and I was pretty confused. This is a link to a previous post that seemed to help me.
http://forum.cakecentral.com/modules.php?name=Forums&file=viewtopic&t=490643&postdays=0&postorder=asc&&start=0

Any chalk that says non toxic is fine & most chalks are non toxic or children wouldn't be allowed to use them. I use an xacto knife to scrape off what I need, it works beautifully. Dry dusting works very well & then you gently steam the item, it gives a lovely shine.

Thank you Im looking forward to trying this tomorrow