Gday Red,
Yep, oven cleaner works a treat. I've found some liquid oven cleaner at Bunnings (hardware chain store) that I paint on with a brush, leave on for a few minutes, then scrub off with coarse grade steel wool. Rinse with water, repeat as required. Spray can oven cleaner works fine, but you get less cleaner per dollar, and I find tends to be more fumey (read, burns your lungs...)
I've occasionally used a bit of vinegar to neutralize at the end too, before final rinse. Lessens some of the blackness you get.
Progressively finer steel wool gives a great shine. Finish with Autosol metal polish. New-looking swingarm in an hour tops
Cheers, and hope you are feeling well
Geoff