I know I can waterblast this stuff, but it'd be nice to kill it and loosen it first so I could be a bit more gentle with the blaster.

Had a good search around and read, and the following things are possibilities:

1) Baking soda - mildly alkaline, dissolve, spray/brush on, blast off later.
2) Vinegar - mildly acidic, spray/brush on, blast off later
3) Alcohol - weak solvent, evaporates away

I guess I'm most worried about the rubber seals and crevices etc. Window rubbers/scraper/strips/seals. In around hinges, gutters, etc. Stuff like that. l can easily clean the large obvious areas, but I want to get into places I can't see well/at all and do so safely.

I don't really want to put vinegar liberally onto a car as it'll promote rust wherever it ends up! No thanks! Maybe in a controlled way in certain places, though? Not currently keen.

Alcohol worries me. It can hurt paint for sure.

Baking soda seems like it'd be safe and could possibly kill off the lichen, thus loosening it. Win?

Any/all thoughts/methods welcome! More the merrier.

I also have the 244 parts car to practice on. It's had a strong alkalai on the right guard for a week or so. I expect damage there, but don't care. Lots more to play with, though. It's not particularly clean.

Shoot! :-)