What to use to clean years of mold off the paint

[Dead Parrot]

Try just soap and warm water first with a scrub pad. Not all tree sap is as permanent as elm tree sap. The black could be mold or rubber/carbon from a nearby highway. A lot of times, that old original paint will buff up nice. Not sure how much clear coat was used in 74.

If you start with industrial strength cleaners and/or abrasives and it turns out the black is just decades of dirt and grim, you might wind up damaging what was a salvageable paint job.

[75C10]

Pressure washer. Just did this with old paint covered in sap, bird poop etc. Came out amazing