Long term storage and humidity has left the headliner covered in mold; it's a 1982 and the material feels like vinyl? I was considering using a Mr clean pad or a fingernail brush and bleach.

 

start by wiping it with a mild bleach solution and a damp microfiber cloth
be very gentle with the brush and don't introduce too much water, it could loosen the adhesive behind the vinyl

 

Bleach did wonders. Killed the mold, anyway, and brought the vinyl up bright. Car seems so much "lighter" inside. I used to habitually dye headliners black in my furrin cars, but got out of that when I was building Falcons.