Consider buying some BALISTOL (Brownell's has it). This comes as a concentrate - dilute 1:10 with water. The product creates an oil-in-water emulsion that will wash out salts that will lead to corrosion, yet leave a thin film of oil upon drying. Stuff is great - I swear by it.
have lots of nagants-psl's-and shoot Bulgy surplus in my 74'
Boiling water-good flush-ammonia-then some CLP-The boiling hot water with a nice little funnel to run it thru the gas system and bore will get the metal so hot it dries almost instantly.Then a good swab with clp and good to go.
In the last 5 yrs i know i have fired 5K or better of corrosive ammo.Never
Had an issue on any of my rifles.
The #1 thing is water or soapy water, I have heard of some shooters using Wendex. That gives just enough ammonia to act as a wetting agent for the water. But it all comes back to water.
Here is a link that could tell you more.