Spitpatch, tranny fluid? good call, i'll try it!
That's ATF AND acetone, mixed 50/50. ATF alone won't do it.
The identification of the barrel as a Beals might be from a stamp. I believe the Remington-Beals revolvers were marked "BEALS PATENT SEPT, 14, 1858..." on the barrel.
This could be one of the second design Remington Army revolvers; they had the frame cutout that exposed barrel threads and later production included the cylinder safety notches. They were stamped "PATENTED DEC. 17, 1861...", but some may have used the barrels stamped with the Beals marking. It's also possible it was put together or repaired from parts by an armorer during the war.