Hi all I am working on several things but two of my projects are a 1980 Bianchi Piaggio Astrale Standard and a 1970 Schwinn Super Sport. Both bikes have been in a barn in Western NC for 20 years and are quite rusty. I have some pics I can post, but trust me when I say they are very bad. The Astrale's wheels were completely shot as the chrome was all peeled off, and so were the handle bars. I have been able to clean the aluminim stuff, and since it had crap components from the get go i am going to make this a fixie. My Super Sport however has all of its original parts and they are all really bad corroded. I have tried naval jelly but it did not help much. The rust is just too bad. How do guys restore these old barn find pre-war bikes that I have seen with rust like mine ??

Hi Karlkafer08 - Welcome to C&V. ..

Oxalic Acid (wood bleach from the Sherwin Williams Store) is the most popular medicine here for rusted chromed bits, electrolytic rust removal is an option for others, but there IS A LIMIT on what is salvageable/worth saving.

Without pictures no one is going to be able to offer a guess

Search is your friend. Rust has been discussed literally hundreds (if not thousands) of time. Removing rust is one step. But depending how far the rust has gone, if the frame is compromised, then it is time to strip the parts for another day.

Without pics, no idea on whether you are to that point yet. And even with pics, until you strip the bike down, you often will not know for sure.

Google: oxalic acid site:bikeforums.net

Attempting to bring an old bike back from the dead is a great learning experience, but as already mentioned, there ARE limits, so if and when you run into a drop-dead issue, you'll know what to look for the next time you think about fixing a different old bike you find.
The effort to return function to vintage mechanical things is it's own reward, but don't be surprised when one small area/part kills the project. Even stuck seatposts/stems can be cut out/released, but I'm just envisioning the toil and sweat it takes to do it without damaging anything else! Been there/done that a long time ago BC (before craigslist), so nowadays, I'd rather find a project with less "patina" to invest any significant effort/cash.
Good luck!