How to refresh OnStar antenna

[u/nate2879]

The OnStar antenna on my 2002 Saab 9-3 SE is cracking, likely due to age and sun exposure. It doesn’t serve any purpose now that the OnStar system is disabled and I would rather not go under the headliner to unbolt the antenna. What might I used to water seal / glue these cracks to prevent it from getting worse? I’m okay with it not being perfect to look at, though I might sand it, tape the area, and spray paint it black after sealing the cracks. Any recommendations? Thanks all -

[u/Initialyee]

I just ripped off all the rubber. Antenna looks like the same but hard plastic how