I am curious about the name of the cleaner and oil that you use and whether you live in a high humidity part of the country.
Not to preach to those who may know more than me but there are degreaser type cleaners and there are solvent type cleaners. The difference is that solvent based cleaners are metal-aggressive and dissolve
copper and lead whereas degreasers are mild and remove grime, oils, carbon and powder. A degreaser will help remove but not dissolve copper and lead, if those substances are sticking lightly via powder or carbon residue to the metal surfaces.
When necessary, the solvent cleaner should be used where needed and probably not on the outer slide. After using a solvent and it has dried, some manufacturers say to clean the metal with 90+% isopropyl alcohol to remove the solvent's residue. Then apply the oil. I think some people are not spending the time to remove the solvent residue or are storing their firearms long-term
after applying an all-in-one product that contains a solvent type cleaner.
The best approach is to avoid the all-in-one products (a.k.a. CLPs) that contain a solvent
type cleaner. Buy separate bottles of degreaser, solvent and oil and use each based on need. An all-in-one product (e.g. Ballistol which contains mineral oil, alcohol degreaser and
a mild solvent
) does not give you that choice. After extensive research my choice is the Mil-Comm family of products sold under the NRA brand name: shop produtcs
Maybe this will be of help. I found this remark from another thread: "A combination of humidity, heat and various chemicals, including some of those found in common cleaning solvents
can break down the polyfoam (in your Springfield gun case) into various acids, etc. that will attack metal." So if that is true then you don't want solvent (or solvent residue) coming into contact with the foam in your case.
And this is interestsing: http://slip2000.eu/media/lubricant/C...n_Analysis.pdf
If they had used Mil-Comm's oil (MC2500) rather than paste (TW25b) in that test, then the rust would have probably been less because the oil seeps better into the metal.
I found these videos of amatuer experiments to be a real eye-opener:
All of the above is my opinion. Your view and results may be different. I am not a shill for any manufacturer or product, and I am not an expert.