We have an 850' drive way - curvy and at a slow incline. Over the years the gravel (3/4 minus) has packed in to give us a very hard base. The drive way has a nice crown with very small drainage ditches on each side. Every year I use a rear blade, set at an appropriate angle and with top and tilt I redo the small ditch and at the same time throw up the migrated gravel - and some dirt will come along with that. After doing this in each direction I will have a nice cleaned up drainage ditch on each side and will have piled up gravel and some dirt on the crown. Then I set the rear blade straight and make a few passes to spread out what I have tossed to the middle. The dirt will end up working its way into the gravel and then not be that visible, and any weeds or whatever will die. This is in Central California - weather and rain patterns elsewhere may make this less effective, but it works well for us. Rarely have I had to do this more than once a year. You can experiment with the blade's angle to see what works best. I usually work it with a couple of different angles.