I like the commercial pre-mixed rust removers the best. Most are the safest and easiest to use, but you're right, they are way too expensive for large items, like a bike frame. Some are extremely hazardous too. Read the label before you buy. I think I've tried them all. The fastest acting was Crosave automobile wire wheel cleaner. Instant and great, but the most deadly stuff I've used, next to muriatic acid. Badly rusted old S2 Schwinn rims look like new in a few minutes, but like I said, the stuff is deadly. Not for the hobbyist. There is a product sold called Acid Magic, that works great, and has way less fumes than muriatic. I left a Schwinn springer yoke in Acid Magic for a week. I forgot about it. Not only removed the rust, but every bit of chrome. Terribly rusted iron can be dissolved away using these acids, but they always keep working , unless thoroughly neutralized afterwards. Steel covered in thick rust will be brought back to virgin metal, but will re-rust immediately as the acid causes additional rust to start the moment the metal is dry. These acids are used to make new steel products appear old and antique, as they oxidize the metal, leaving a cover of rust when not neutralized. The best rust remover I've seen used here on the CAbE, was by Caber, Chi-town. He's no longer around here, but a few years ago he got stuck with a load of lime juice. I guess he used it in the bakery he owns here in Chicago. [ Don't get me started on how much I hate Chicago. God, why did I say that word? How much do I hate Chicago? Let me count the ways .... ] Anyway, lime juice works as good as any of them.
When using hazardous chemicals, I let my wife clean them. She typically dresses like this and has very long nails. Great for digging out pockets of corrosion. We've been married a long time. Some women lose their beauty, but she's an exception, don't you think? God, I love her, that woman of mine. . .
Her burka covers a nasty scar on her chin.[She's very self-conscious about it] A rivet let loose on my air compressor and clocked her under the chin. I dug it out with a Schwinn kickstand pin removal tool. She made me get rid of the compressor. Fellow CABE member "Neanderthal " now has it in his garage.
Took her to the "Corn Museum " afterwards . That made her happy.
A before and after of Oxalic Acid
These are our children, getting ready for the 4th.
Above is an example of what you can do with parts bought at swaps or here on the CABE. The sky's the limit. Have fun, and work safe.