Weathering with pastel in different ways question.

I have done some weather with pastel where I sand off some dust and brush it on, or where I draw on the model with the chalk and then smooth it out with a brush. I have been happy with both ways. Here are some examples
http://www.happinessismandatory.com/misc/SW_ATST.htm
http://www.happinessismandatory.com/misc/Mad_Max_Interceptor.htm

But I was looking though some old FSM articles and they guy ground up the pastels and then mixed it with water and brushed that own. It was a F-16 Tomcat model. Has any one else done this? What are the pros and cons of this over just brushing the dust on?

I am fixing to weather my Revell Viper model
http://www.happinessismandatory.com/misc/Colonial_Viper.htm

And I was curious about it.

Thanks

I think some pastel chalks are water soluble others oil based…? , might just sand some off and see what it does…maybe add a drop of detergent too.