Marin £25

[kingoffootball]

Unfortunately the material itself is compromised.
This means you'll need new "nipples", which come with the spokes - and take care to preserve the threads in the rim.
I'd say the rim threads tend to be ok, although you might want to clean the threads.

I have plenty of spare nipples, it's removing the old ones which is causing the issue.

 

[bikeworkshop]

Can you post a close-up pic? I thought you had those captive nipples!

 

[kingoffootball]

Can you post a close-up pic? I thought you had those captive nipples!

I'll try to take one tomorrow wwhen the light is better.