Clean the thing first.
Yeah, I know... it's a mess. But the odds are it's an oily, greasy mess. And there may still be some paint under all that rust. Electrolysis does not work on grease. Nor paint. You'll end up removing the rust from all around the greasy or painted part... which may be what you want but usually isn't. So degrease it.
A hot solution of lye (ie, the traditional 'hot tank') is the time-proven method. Of course, if get some on you, you tend to jump around and make funny noises. TSP -- trisodiumphosphate -- is a more benign getter of grease and does a pretty good job on paint. Just keep boiling the dirty part until it's down to Basic Rust then pop it into your electrolytic bath. (Be sure to use real tri-sodium phosphate. There is a common household cleaner with the BRAND NAME of 'TSP' that does not contain any phosphates at all. Paint department usually carries it [you use it to scrub old paint before laying on new]. )
Same holds true for your iron electrodes. If you clean them before wiring them up they will have more effective surface area.
Handiest clamps I've found were pieces of copper pipe. Cut off a piece about an inch long, wrap your wire around it and solder, then drill the thing to accept at least three sheet-metal screws. Slide over the re-bar, tighten the screws, connect the wire and away you go. The re-bar gets eaten up but the clamps will last just about forever.
If you've used a concentrated salt solution for your electrolyte then you'll need to BOIL the part in clean water once the rust has been removed. The derusted, boiled part will develop a haze of rust as soon as you lift it from the boiling water so be ready to deal with it. Either give it a shot of primer as soon as it's dry or hose it down with WD-40. (I don't recommend the use of lye. Any salt (as opposed to acid) will work. I use washing soda.)
A big advantage to electrolytic rust removal is that it only takes away the rust, not the metal attached to it. With sand blasting, everything goes -- and leaves a surface that's rough as a cob.
Save the Coca-cola for rotting out your teeth, the way God and the American Dental Association intended. If you got rust, there are smarter, less expensive ways to get rid of it.
-Bob Hoover