Adjusting servo arm

[RC Guy]

I put my aileron servos in neutral with a servo tester but the servo arms were not put on right. However there is a foam lip so I can’t unscrew them. Should I push the foam down with a screw driver or make a small hole?
This is on the Freewing F-8 Crusader btw.

[boomer108]

I have taken a heated Phillips screwdriver medium size shaft and made an angled slot to get to the servo arm screw. Works great and looks factory made.