1985 300D Turbo.

Right rear axle boots torn. I had re-manufactured axles (CVJ Axles Inc) put in by an indie about 10 years ago. Charged me 4 hours labor which I thought was fair and he didn't care that I supplied the CVJ axles plus some other miscellaneous parts (I think an axle bolt which is pre-coated with something that Mercedes recommends and I also supplied a washer that should not be reused --- I have to research as I don't currently recall). So my plan is to re-order some axles and parts and have the same indie put them in.
Eventually I will have to return my current axles to CVJ Axles Inc to get my core charge back.
So:
1. Can I use the car as is for a few 10 mile round trips, or do I risk causing damage that renders the axles useless to be re-used by CVJ Axles Inc. Right now the axles are not making any noise that I can hear while driving.
2. Would it be helpful to stick in some type of grease and then duct tape the boot closed when making these short trips? When I stick my finger in the ripped boot I feel a smooth axle. No gear teeth or metal that would move against other metal. So why is there grease there?

 

Added 2 photos.

 

Ordered axles from CVJ. In the meantime I purchased a grease gun and long tip from Advance Auto to fill the can with high temp grease to hopefully prevent any/further damage. Despite the huge opening in the boot, I could feel grease in the can with my finger. Also not hearing any clicking while taking a short drive. Advance Auto also had the blue boots that come in two sections and are glued together as shown in this video: . Considered using them, but ruled it out.

 

Garage installed my axles 2 weeks ago. Same place did the same job for me 9 years ago and charged me the same price. Told his son I'll be back in another 9 years and wanted the same price when he takes over from his dad. I'm pretty happy with the price which I state here as it may be useful info for someone shopping around. $350 labor, $25 supplies (Diff Oil, probably rags, maybe diff gasket, didn't get specifics), $23.81 tax. Total $398.81. He didn't mind me supplying parts as some places do. I supplied CVJ rebuilt axles, diff seals, C clips, crush washers, shims which he said he would modify if necessary.
The only other price I got was when I was shopping around 9 years ago for the first job. That garage said book price was 7 1/2 hours labor and he wanted to supply the axles, so I went elsewhere.
Also let me put in a good word for CVJ Axles. I returned the old Mercedes cores and they deposited the core charge in my bank account next day automatically.