Tahquamenon

For In-lines with removeable breech plugs:
With the muzzlepointed down and the rifle un-primed, just remove the breech plug, then turn the muzzle upward and dump out the powder and then slowly push out the projectile out the projectile from the muzzle to the breech end.

For caplocks and flint locks and other inlines without removable breech plugs:
Un-primethe rifle. Use a ball-puller attachment to your ramrod on one end and a t-handle or rod puller on the other and slowly pull out the ball or conical.

Or, there are available Co2 dischargers that have adapters for both inlines and sidelocks. Like the one from Cabela's that pse-archer mentioned.

Tahquamenon