It’s true, according to Cook’s Illustrated - the old fashioned way is to build a fire and put the pan in and let it burn out, but they tested the oven cleaning cycle and said it worked like a charm - just smack the dust off it and reseason.
I used to use spray-on oils, but had a problem with build-up. Read somewhere (Harold McGee?) that the problem was the lecithin, so I stopped and the problem went away. Besides, it isn’t necessary to oil a properly-seasoned pan for storage.