"Back in the day" when the revolver was King at the shooting matches, the 148 wadcutter in a mid-range load was THE target ammo.
Shooters used lead for several reasons: It was THE most accurate, it was easy on the barrel, it was cheap, since many casted their own bullets, and the barrel lasted virtually forever.
Hard cast lead wadcutters don't lead MOST revolver barrels and chambers as badly as softer lead or hotter loaded defense ammo, but in all older revolver shooters equipment, you'll find a Lewis Lead Remover Kit.
This is a special cleaning kit available from Brownell's, that's been used for probably 50 year or more, to safely clean expensive revolvers of leading.
To clean a revolver properly AND WITHOUT DAMAGING IT, I recommend the Lewis over "expedient" methods you read about on the internet.
The Lewis is the only way to really clean the forcing cone, and removes all lead from the bore without risking damage by "Billy Bob" cleaning methods.
While the Lewis also cleans the cylinder, I recommend using Brownell's bronze chamber cleaning brushes for that, since it's faster, and just as safe.
If you shoot Mid-range lead wadcutter target ammo, and clean with the Lewis kit, you'll have the most accurate loads possible, and your Python will last forever.
Among the "expedient" or "Billy Bob" cleaning methods that I've seen cause damage to guns are:
Shooting jacketed bullets after lead to "blow the lead out".
(This one can blow a ring or bulge in the bore, and in any case, actually "irons" the lead into the bore, making it harder to remove).
Using steel wool.
Using vinegar as a bore solvent. (EATS bluing).
Using mercury. (Eats YOU).
I've never been able to fathom WHY someone would risk an expensive gun to save a few cents on proper equipment and chemicals.