New owner...new member...cleaning question

First I'd like to say what an amazing community you all have created here. I have been lurking for some time while researching our next camper.

Yesterday I drove to Louisville and picked up our new to us 2009 2916. So exciting.

It is in excellent condition but as you can see in the attached picture, there is black mold like streaking on some of the silicone joints.


Have you all found an effective way at cleaning this up? We are going to spend some time today getting it in top shape for this Spring and Summer

Thanks

Dave.