Undercarriage rust prevention...1987 Carreraun.

[giacmosuaviet18]

Undercarriage rust prevention...1987 Carreraun.
Moved this topic here as technical side suggested. I have a rush free original paint 1987 Carrera. I'm in the process of cleaning up the undercarriage in fenderwell. I thought that black coating that is now coming off was old undercoating. However others on the farm feel like it maybe old cosmoline. Your thoughts? It has been suggested that I use mineral spirits and scrub brushes to remove. I'm not trying to make a show car but it looks like it has leprosy with the way this stuff is coming off in patches.

Thanks in advance for your input.

Here's an example from rear fender well area.
__________________
Jim
1987 Carrera
2002 BMW 525ti
1997 Buell Cyclone cafe project
1998 Buell S1W: "Angriest motorcycle I've ever ridden."