Tangkitn / Pandat with motive

[David]

Originally Posted by kino

I tried the toothbrush and WD-40 method before and was unsuccessful. I was tempted to use fine steel wool but I’m afraid of the possibility of snagging an inlay.

This looks like red rust to me. Photo is blurry.

I don't see the rust in the photo, but if you see firsthand i don't doubt you.
I would try spraying on WD-40 and really letting it soak in for a bit before brushing.
As for steel wool, 0000 or even 000 grade should not cause any damage, at least not in my experience. As always, work slowly and carefully.