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