A few months ago I posted the pix below and asked what the herd thought it could be. I got a lot of responses from a gasket leak to normal condensation from short trips to a bad flux capacitor (not that because I replaced the flux cap just a week before).
I remembered seeing this condition before so I went with goo build up from short trips.
I use Mobil 1 5W-30 oil with a filter change at each oil change usual at about 6-7 K miles.
I went to Penzoil Platinum with NO changes in driving patterns and although no pix is included, the filler stayed clean as the day it was new.
Mobil 1 is good stuff but it does often show high iron when an oil analysis is done and it appears not to handle short trips as well as Penzoil.