I posted this on the FB thread, but I once saw a suggestion to use Mylar
backed sandpaper for thin  gaps, less thick than paper or cloth backed, and
still very flexible.

https://www.amazon.com/1X30-2000-Grit-Polishing-Cushioned/dp/B08CY6MM6X

Something like this, can be cut to narrower or shorter once you get going.

I used to have cord abrasives for stripping paint off a turned table leg,
and this is finer still.

Kirk in Half Moon Bay, still fishing through the haul of tools from my
buddy's garage.

On Mon, Mar 6, 2023 at 11:13 AM Dennis Heyza 
wrote:

> Narrow strips was what I alluded to in my reply. Just cut a strip (found
> it helps if you cut 1" and fold it over to 1/2"). If you cut it long enough
> (say 5-6") you can easily pull it taught above/below the scrollwork and
> sand - sometimes up/down, sometimes side to side. You can easily get this
> is pretty tight spots.
>
>


-- 
Kirk Eppler in Half Moon Bay, CA