If you want to remove rust and the part is heavily rusted try "Evaporust". It removes rust better than anything I have ever seen. It is positively amazing. It also removes anything akin to rust like bluing.
If you have a heavily rusted receiver or part you think is beyond help give it a try. I used it on an LC Smith that had been on a garage shelf for 30 years. I tried it instead of scrapping it. My brother now has the gun back in use after a reblue. It looks almost as good as it did when he got it in 1956.
It is made in Minnesota I think. Midway sells it for about $30 per gallon. Biodegradable and non toxic.
