Any such 'seasoning" is built up fouling mixed with lubrication that is building up to the point that accuracy falls off. Even Dutch tells you to get the bore clean to take advantage of the spin imparted by the twist in the barrel. While Dutch advocates the use of WD40 as the cleaning agent (no soap and water), he expects to remove all the fouling from the barrel and that includes what passes for "seasoning".
Or maybe RV antifreeze, but you don't want to use Ethylene glycol, it's poisonous.
Necchi isn't here, but I can provide some of my experience.
I've used it, and it works fine.
I won't comment on what to use for cleaner, but a locksmith told my brother that the best friend of a locksmith was WD-40 as it brought them more business than anything else. But it did work for one purpose of mine. For several years me and another fellow ran a Junior rifle club thru the DCM program. The storage area for our firearms was a loosefitting steel cabinet and a high moisture area so storage of the firearms-was tough.When WD-40 first came out I thought I would give it a good test, so I took half of the rifles and soaked them with WD-40 and the others with just regular gun oil. When I checked on them a couple of months later, the WD-40 ones had turned pure white on the stocks and on the actions, but I was able to remove it very easily and the stocks just shined and the barreled actions cleaned up easily with Hoppe's number nine. I re-sprayed them and it was probably four or five months later that I had to reclean them as we were beginning our shooting season. I wouldn't know about a long time storage but it sure worked on these guns. There was absolutely no rust though the guns did have a Parkerized finish on the outside which is fairly tough but the bolts and barrel interiors remained rust free. The actions cleaned quite easily with Hoppies #9 any toothbrush. I believe it was the high moisture that turned the guns white as it was also quite close to a strong alkali area.
