I've seen rail dust and tar spots from shipping cars in the past. Fortunately, Nissan uses a nice thick clear coat, so when these particles get into the paint, they just set into the top layer of the clear coat. The method to remove is to buff them out by using a "cutting compound" and an electric buffing wheel. After the cutting compound they will use a polishing agent to remove any small swirl marks.
Give it a good close look when you pick up the car to make sure they aren't any excessive swirl marks left in the paint. If so, they need to polish it a little better.
When they are done, you should have zero lasting effects. The clear coat is thick enough that even after this fix, it will last you for a long long time!
Hope you enjoy the Juke!
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Joshua 1:9 "Have I not commanded you? Be strong and courageous. Do not be terrified; do not be discouraged, for the LORD your God will be with you wherever you go."