Just wipe it down with a good car wash detergent and water. Use a non-abrasive Scotch pad on any corrosion/rust that you find on non-painted metal. You can often "brighten up" painted surfaces by simply wiping them down with WD 40. Wipe every thing down again with clear water and then carefully wipe the steel rims off with rubbing alcohol several times. Lube the brake and shift cables with a little oil and consider repacking the wheel, crank, and steering head bearings. The brake and shifter arm pivots should get a drop or two of oil as well. Replace the tubes and tires if any cracks can be seen in the tire side walls. Take a look at the late great Sheldon Brown bicycle maint and info web pages (Park Tool also has very good "how to" bicycle guides and info). Your project could be a good learning experience, or a waste of time and money. It just depends on how you go about it and what your expectations are. Note: Please take very seriously the advice and warnings on steel rim caliper braking problems (I strongly recommend that you do not ride any steel rimed bicycle down even the slightest hills until you're familiar with steel rim caliper braking power (or lack thereof). Riding steel rim caliper brake equipped bicycles in the rain and/or wet conditions should be strictly avoided at all costs.