deskthority

I got an f122 and when I opened it to clean I noticed some of the flippers have this weird substance on them. It looks as though some liquid got into the assembly at some point and dried up.
Here's a photo:
I have tried soaking them in dish soap, 99% isopropanol and scraping them and it does absolutely nothing. If anyone has any ideas what this is / how to get it off I would love to hear
Regards

Not sure - but if it's not affecting operation, I wouldn't worry too much.