I have a gravel driveway that has nice grass growing in it, weeds, etc. Four years ago, I had it scraped and re-graveled. Now it needs more gravel and lots of help! What is the best method for removing the grass, weeds and what type gravel to use? The base is there and very hard, so do I need to have it scraped or just add to the top. What is the best method to rid the grass & weeds--and would crusher run help kill the growth? Suggestion on size of gravel? HELP!!