DO NOT use oil (olive or any other kind) on snakes- the idea is to smother mites with it, but the dish soap/soak is the better way. Oils mess up their skin & future sheds, plus they can get it in their nose, etc- just don't...
I hate mites, they're awful, but happily I've only ever had 2 (new) snakes with them, & that was many years ago- none since. I agree with using the least harmful methods (to your snake).
Don't forget that mites can transfer on your clothing to your other snakes- so work on the others first, then the one with mites, & shower/change clothes before handling others- just in case. One snake to treat is bad enough.