I have some of these… jorgensen parallel clamps - Google Search I have never noticed glue sticking to the metal bar. I have indoor / outdoor Elmer’s glue on-hand. I will start a test tonight.
@mblatz, can you tell which glue(s) are stuck on the clamps?
@Brian: It’s almost certainly Titebond II or III. The bars on the Bessy are steel…possibly treated or coated or some alloy (e.g. stainless).
I did some experimentation yesterday with some help from Peter G and Ivan. Sandblasting was not really effective, although with a little more time might have accomplished the task. Wire wheel suggestion from @Sk8nmike was far more effective. I did not try steam/water yet, but wire wheel did a good enough job that I probably won’t bother…I have to assume it would be a bit of a mess anyway. Key parts are the serrations in the bar, and wire wheel seems ideal for that anyway.