Back in the late 1960's when I was going to college, to earn beer money I'd purchase or sometimes people would just give me a car (just get it out of my driveway!) that needed work, usually something simple like a new clutch or a brake job. We're talking a $10-$15 POS car. I'd fix the car drive it for a month or two and then sell it for usually about $300 and find another car to fix and sell. Often the car wouldn't have an ignition key any more. No problem, I'd take the lock apart and remove all the tumblers accept for the first one. Upon visual inspection the lock would look okay, but you could usually need nothing more than wiggle a screw driver in the lock to start the car. Don't forget here, I'm not talking about cars that anyone would waste their time stealing.
Steve
Interesting! Wish I was around back then, I'd love a side hustle like that.