Corroded oiler port on Penn 710z handle

[circlehook]

One of my Penns (710z) has athe handle oiler port frozen. I tried wd40, soaking in vinegar and prodding gently with a pick and this has got rid of the superficial crud and corrosion but the oiler port itself doesn't depress unlike  a properly functioning port.

Are there any other tricks I could try ?
Thanks

[Crab Pot]

I'd try penetrating oil and give it some time, like a day or two.