I would clean it so you can quantify the amount over time and whether the leak is becoming worse. When it is clean take pictures and email them to your own gmail or other commercial account. Continue to take pictures and email them to yourself at regular intervals giving you a sort of time lapse photo documentation of the leak. These will be invaluable later if things go to ****. It isn't that you want to go to court, I'm no attorney but I suspect based on an MM action I pursued you will wish you had never started no matter what the outcome. What you're looking for is to protect yourself if the leak becomes catastrophic causing an expensive failure and also in the nearer term to have something undeniable to show the service department about the leak and what it is doing. Is it getting no worse, getting worse, etc. I've come to notice over time. If nothing else you will be able to rest easier knowing exactly what you're looking at. I agree with others though, I would have to think hard before I decided I wanted my engine torn into depending on the leak. A valve cover is one thing but major surgery would have me thinking I might prefer to hold off until the leak became a problem.