Barkeeper's Friend test
Earlier this morning I tested Barkeeper's Friend on one of the racks. I made a paste with the powder and water. Then rubbed it with a paper towel dipped in the paste. It takes off the grime and restores the silver color right away, with minimal rubbing. A dishtowel dipped in the paste would work equally well, plus you don't spend money on paper towels since you can wash and re-use a dish towel.
It would require a LOT of work/time to clean the entire rack, when you consider the combined length of metal rods/wires in each rack, but it's do-able, and does not require a lot of hard physical effort or scrubbing (just a long and tedious process). BF is a mild organic acid, not something really toxic like Easy Off.
My racks did not appear to have any burned on food on them. Rather, they appeared to have the dark discoloration that happens when you don't bother to remove the racks during a self clean cycle. And it appears that BF can restore them in a relatively eco-friendly way.
It could be that older racks are chrome plated and thus cannot be restored by the method above. My range is a 2001 Frigidaire gas convection model and the racks never appeared to be shiny chrome, but rather just low-gloss stainless steel. One could even do this cleaning on a kitchen counter with a bunch of shop towels underneath to absorb anything that drips off the racks. After cleaning, they would require rinsing in a bathtub/shower/outside to thoroughly remove the BF residue.
I don't have a lot of splatters and drips in my oven because I don't roast in open pans all that much. My discoloration was due to ten years of self cleaning cycles without removing the racks. That may explain why the residue came off rather easily with BF: it wasn't baked on food, but rather that dark discoloration they warn you about if you don't remove the racks.