Pressure regulator - removal of regulator piston

[rdivy725]

Greetings! Working on a 82 E21 M10 and want to replace the o rings for the pressure regulator in the fuel distributor. I removed the regulator but the piston stayed in the FD housing. I tried (gingerly) to remove it with a pick. No luck. Suggestions for removal of the regulator piston? Thanks in advance