For the W124 chassis, open hood, reach up into the hole below the star with a pair of pliers, and pull down the retaining clip and rotate 90 degrees left. This will pull the clip down and put in on the "shelf" on the star so you can pull it out.
Put new star in, pull the retainer down with the pliers and rotate 90 degrees right and release.
Do not rotate the clip on the new star out of the car, it turns fairly easily but the spring is strong and it will pinch the you-know-what out of anything that get between it and the bezel. I know, I did!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!