Keeping cables free of dirt when in transporting Any ideas on how I can keep grit and all of the other nasty road stuff when transporting my bicycle 2,000 plus miles this spring to get home? It will more than likely be rain and snow on the way. They will be on a bicycle rack behind our Chevrolet Equinox. 
The suggestion of garbage bags over the cables sounds promising.  



Update:

Thank you all for your ideas.

It looks like I will be driving into wintery conditions the closer I get to home. I wish I could afford an enclosed trailer, but I have no use for it after transporting bicycles. Bicycle covers are great, but they block the vehicles turn signals. I was looking for a low cost solution. I am going to remove all of the cables and wrap parts of the bicycle in shrink wrap.

Thanks again for all of the ideas.
I'm assuming that you're putting the bike on a bike rack on a car or something. Note that different racks and cars can give different amounts of dirt accumulation; for example, the roof of a Chevy Suburban would probably be cleaner than on the back of a Mazda Miata. 

One solution is to just let it get dirty and then clean it off when you get to your destination.

Another is to wrap the bicycle parts in something like trash bags taped tightly to the bike, leaving the parts necessary to grip onto the rack exposed. 

Yet another solution is to put the bike in the car or trailer or something. I can get a 58 cm road bike in my hatchback pretty easily provided I don't need to have someone in the back seat.