Here's my schwinn after some work. still need to get the deraileurs cabled and get some rust off the rims where the brake pads touch.
I have yet some more questions, can I use oxalic acid wood bleach on the rims and cranks? and any idea on the year?

Look for the serial number on the head tube just above the bottom bearing cup. That will tell you the month and year the frame was manufactured.

Can you use oxalic? Yes, after you disassemble the parts. On the wheels, you can just take them off the bike, and rotate the rims through the bath (tires and tubes have to come off of course). Each portion of rim will have to sit in the bath for many hours. Note, if the chrome is gone under the rust, it is gone. Oxalic will not replace missing chrome.

Before:




After:

The few spots I took a wire brush to still had the chrome. I was just wondering if the wood bleach would cause any excessive corrosion.

Don't worry about the oxalic acid. But your wire brush is a problem, it removes chrome and rust. It does not know the difference. Oxalic just converts rust chemically. I have ruined some chrome parts using abrasives. Never again.

Thanks wrk101 and Scooper. Apparently the frame was manufactured in July 1979.