Yeah the chlorinated solvents were among the first to be reformulated, as the chlorine component is the "bad" ingredient that hurts the ozone. So chlorinated cleaners, freon's, and propellants were changed to chlorine-free chemicals. Which means they don't work as well and typically are not as stable.
The old Berryman's carb cleaner (I think it was called Chem-Dip) was so freaking powerful I remember it'd start burning the skin on your hand after a short time. But geez it would melt gunk off of carb parts! The new stuff you have to get a brush in there and scrub the parts clean.