Or remove the breech plug, remove the charge, and push the bullet out. Then you can give it a "deep clean" for winter storage, including the breech plug threads, nipple, interior of the breech plug, etc. Powder and powder residues can be corrosive to your bore. Maybe Sabotloader or someone else with more expertise can also weigh in.
If I am storing my muzzy for a long time, I also like to apply a tiny amount of a gun oil (or 3-in-1) to a patch, and lightly oil the bore as well to prevent any possible oxidation.