In real warfare, it was common practice to pee down the barrel when it got fouled. The mix of uric acid and a hot barrel used to do the trick. NPC on a re-enactment site though. If you had a rifled weapon such as a Baker it was even harder to get the ball down even with the greased patch. All riflemen in the 95th were issued with a small mallet to aid in loading by striking the ramrod when the ball stuck.
I never saw one of these employed in the Sharpe series, probably because all their so called Bakers were smooth bores. You don't need an F1 license for those, just a Shotgun certificate.
Rob.