Buy him a stack of cheap towels at Wally World and wipe him down thoroughly when you both get in. Keep them in a separate hamper for doing laundry and wash them all together.
You're going to make him very uncomfortable with dried out skin. If you have OCD about cleanliness a GSD dog may not have been the right choice for a new addition to the household.
No one says you can't keep a clean house with a large GSD in the home, but YOU are going to have to work at it that much harder. The dog shouldn't suffer for what he/she can't control.
Wintertime is particularly messy for any sort of house dog, but especially large breeds.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf
An Unhappy German is a Sour Kraut!