I assume this is a Mercedes CJ7? Just kidding.
I've been through this before on a 123 wagon my wife had. The sound didn't bother me, but embarrassed her.
I forced as much grease inside the boot as I could, using Harvey's method. I then wrapped the boot in duct tape as best I could to keep the dirt out. The grease will attract dirt like a magnet, if left unprotected. The dirt will then finish off the balljoint quicker than if you were to leave it dry. I used this for a few months until I pulled together the tools and balljoints. Also, if I remember correctly, I lifted the car and let the wheel hang while I forced in the grease. This allowed the grease to get underneath the ball easier.
To save Deezel some trouble, don't get under a car that is merely hanging from a floor jack, use some jack stands under the unibody "frame rails". Always be safe when getting underneath a raised vehicle.
Best of luck with it,
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in