Are there any experts on fountain pens on this forum?
My mother had a couple of old fountain pens lying around and it turns out one of them is a Montblanc No. 32.
I would really like to get the Montblanc writing again, but it seems that the piston is stuck. I can only turn it about half a rotation before it stops completely.
I can also see that the feed colored blue and covered in old ink. I've tried to let it sit in a glass of water but that doesn't seem to do the trick.

Any ideas on how to get this beautiful pen writing again would be greatly appreciated.