Anyone remember this stuff? From what I can tell its Hungarian heavy ball 7.62x54r with a steel core. I know the supply is dried up so I can't find much info on it.
Windex and ammonia are useless. There is nothing that neutralizes a salt which is what corrosive primers leave behind when fired. You need water to dissolve and wash the salt away. Adding some soap to the water as a surfactant will help float away the salt and some dirt too. The only thing ammonia would do is dissolve copper deposits after some time and windex has very little ammonia in it so the water in it is doing the work of removing the corrosive residue. You're just wasting money using anything more than warm/hot soapy water.
The earlier dated ammunition , dated 1953, was lead core and for its age was accurate out of Finn M39’s. If its similar to that year you should be pleased.
I have most of a 440rnd tin of Russian 7N1 left. The only x54 gun I have nowadays is a ratty looking T53 but it shoots straight. It's kind of a shame to shoot such a hard to find "sniper" round through a carbine though.