After reading S&S 2.0 I am considering the use of chalk. However, I train in my living room and don't want to ruin my nice carpet Just kidding. We have a hard wood floor in our living room. That being said I still want to minimize chalk dust and chalk stains. Does anyone use chalk bags? Chalk blocks? Chalk balls? Liquid chalk? At the moment I am considering liquid chalk or chalk balls as both options seem to minimize unwanted chalk spillage. But I would first like to hear your recommendations or experiences before ordering. Thanks.