I suggest you not use aggressive means to clean it.
A little copper wash hurts nothing.
The trick is "do no harm"
A LOT of harm has been done by "cleaning"
We went a long time with Hoppes #9,cloth patches,and an occasional bronze brush.
Now we have Bore Tec Eliminator,Wipe Out,etc.I think the Montana black nylon brushes work good with modern solvents.
For preservation,a light coat of RIG rust inhibitive grease is great in the bore,but develop a habit of always running a dry patch or two through the bore before shooting.
Grease in the bore can increase pressure or even act as an obstruction.