Headlamp adjuster captive nuts

[stag36587]

I've now come to part of my restoration that I've been putting off. Some of the headlamp adjuster screws have broken off inside their captive nuts so I have two questions

Is there an easy way to release the remains of the existing screws? I've tried WD40 so far with no luck. Or would it be possible to drill them out?

Also. Assuming I have to replace the captive nuts - what thread would I need
And where would I get them?

All help appreciated!

Thanks

[bmcecosse]

They are tiny - I doubt drilling will work. WD40 is NOT a release oil...