I've posted this elsewhere.
My parents bought a 1962 VW Beetle Cabriolet, brand-new, $2225, when a standard Beetle sedan was ~$1700 out the door. That Beetle was what I learned to drive a manual transmission while behind the wheel. We lived by Lake Ontario NYS.
One day I was changing a flat tire in the concrete floor garage, using the 'slick jacking points' which were tubular sockets in-front of the rear wheelwell, and beneath the running boards. I was using the OEM jack in that socket. As I started to jack the car, I noticed a flurry of rust chips, steadily falling off the area of the rocker panel. I'd done that before, changed a wheel/tire, but when I was jacking then, I was used to seeing the side of the car rise off the floor of the garage. This time, I only saw the rust chips shower. Then I noticed that the area of the jacking socket was slowly-collapsing. I gave the J-lever a few more pumps, and watched as the jacking point slowly collapsed the sheet metal of the rocker panel, and the rust shower continued. I stopped my jacking attempt, and gave a report to the head of household, "we need another type of jack." The VW Cabriolet was probably 5 years old.
Years ago, at a place I cannot recall, maybe a scrapyard or a yard sale, I bought a set of probably 1/4" aluminum diamond plate welded wheel ramps. They had a too-steep ramp angle to drive-up, but just jack up the front or the rear, and slip 'em under the wheels/tires and you got probably 8-9" of lift. Far better than the plastic ones, never had a pair and never will.