I've pH tested the water after rinsing with boiling water, and the water is acidic. There are vids of kids cleaning AK's in Africa using a bucket of water and a rag, using the rag to squeeze water into the action.. They're pretty much just putting diluted acid on everything. I haven't heard of ammonia being used for this, but I would imagine it'll neutralize the acid and produce ammonium salts, just the same as using things like baking soda (sodium bicarbonate), sodium carbonate, potassium carbonate, caustic soda (lye, sodium hydroxide) and others. Caustic soda method is probably the cheapest and does the best/fastest job of neutralizing the acid, and rinses easily off metals.
Just don't use too much ... caustic soda is highly reactive in any concentration. Use very very little, such as 1/4 teaspoon per gallon of water. Buy some pH test strips (they're like, $1 for a pack of 100 on ebay) and use a pH of 8.5-9.0 to rinse with. 9 is safe enough for your hands without needing vinegar to rinse with after.