Oxi-clean. Mix it in a spray bottle and soak the area and then blot. Instead of blotting it up I used the furniture attachment on a carpet cleaner to suck up the Oxi clean. I then rinsed with hot water from the attachment and sucked it all up again.
Make sure you do not leave it or make it too wet.
Do this three of four times and let dry. If it still shows repeat.
It worked wonders on a previous MH where the roof seams had been neglected by the PO. I was able to get several thousand $ off the asking price and had it cleaned in a week. None of my friends/family could tell. Also had the roof re-sealed with enternabond and the AC seals replaced.
Unfortunately the shop that did the AC seals did not tighten them down enough and I ended up with another stain - same process worked again.
I have before and after pics somewhere.
HTH
P.S. Cover your furniture/seats when spraying - oxi clean turns white when dry!
2008 Holiday Rambler Scepter 42 PDQ
2018 Ford Edge SEL- Ready Brute Elite Tow Bar/Blue Ox Base plate/Patriot Brake System
Retired Canadian Army WO (1971-2000)