Maybe not in the 1700s, but according to Ned Roberts, you used HOT water to wash down the bore and swab dry. Apparently the heat helped evaporate any moisture left.
This is sorta apples and oranges if we are comparing 18th c FL to late 19th c percussion.
Ned Roberts lived in an EXTREMELY civilized and safe place. HOT water works but it promotes flash rusting, I quit using it because of this. Soapy hot water is even worse. HOWEVER, remember that the caps Roberts used were very CORROSIVE. Much like modern substitute powders with Potassium Perchlorate in them. This fouling needs hot water and lots of it. BP used in FLs is more benign.
But BP is not so aggressive and cool or tepid water is just as good. If soap is added it has to be rinsed with clear water since soup is also corrosive. The Chlorate (Caps) /Perchlorate (some modern powders) fouling will attack iron/steel even under and oil film.
If using the breech in the bucket technique then the dirty water cannot be used as a final rinse. Use clear.
Now if I were on the plains or in the Mountains with a "Brigade" in 1830 I could pour hot water down the barrel to wash out the passages etc and dry fast. But if I am out alone? This has to be done more carefully.
Also note than PERCUSSION guns are more difficult to clean than a FL is. More places to get plugged with fouling or tallow and fouling if this is used.
A plain breech flint gun can be wiped with tallow, the pan and frizzen wiped the the vent "feathered" to clear it then reloaded. A percussion gun may need a water flush to remove the fouling in the powder channels in the breech or the drum. Many old drums had no clean out screw and once plugged the channels are plugged. So by Roberts time the cleaning methods may well have changed simply due to the differences in how the percussion guns were made and the aggressive fouling produced by the caps.
I much prefer the breech in the bucket method or Track of The Wolf's FL cleaner than clamps over the vent with a tube to the bucket, if it can be made to work. But its not practical for the typical long rifle.
Chapman in "The Improved American Rifle" cleaned with Sperm Whale oil IIRC and then when he was ready to shoot again pulled the nipple, put some powder in the chamber under it, replaced the nipple and fired to blow the channel clear of oiled fouling which wiping with an oily rag would not touch and may have even packed with fouling. This from the 1850s. HOWEVER, he was an eastern TARGET shooter.
By the time Ned was using a rifle breechloaders were the standard and MLs were fading from use he was born in 1866 after all. While this makes him a wonderful source for the late percussion era, its not necessarily correct for the FL era 60-100 years before his birth.
Dan