you can make hash but it will be incredibly low in thc so theres no point really, if you keep them alive you can experiement with them, lst them, top them, ext ; you can also collect their pollen if you every want to reap a seed harvest.I personally chop them up and throw in with the compost in my garden although with bigger crops would need to far more subtle, i knew some growers that used to put them all into bin bags and drive them to the dump.