cut tiny pieces of the tar and mix is it with baking powder so it will look like a salt and pepper kinda mix, but mostly baking powder... people would buy a gram of that stuff for 60 bucks while only 20 percent of it was originally the tar which was obviously already cut.
or if you really want to get into some trouble just mix syrup with instant coffee and but it in a balloon , or you could just fold up a jolly rancher rapper and put it into the balloon. just be creative bro.