When I went to check my lifters after pulling a cylinder, the sockets and plungers would come easily but the bodies resisted. They would start to move then the plunger would lose the grip on the body.
I went to the hardware store and bought a 3/8 - 7/16 expandable rubber plug about 1 1/2 inches long. Using a long 10-32 machine screw fitted with a tightening nut and washer, I expanded the plug until it was a snug fit when pushed into the body. Worked slick! The bodies easily pulled free. Remember, no magnets here. Jake