More than likely you don't need a new nib.
Waterman subsection could tell you what exact type and where to get one...if we can't do a quick cure here.
First, stick the nib up to the section in some water for a few hours, so the ink can loosen up.
A loupe of 10X in good glass or 40X in a cheap Chinese loup will tell you if the tines are aligned.
Scratchy is mostly misaligned tines.
A honking big magnifying glass won't do. If you know a jeweler, his eye 6X loupe would tell you if one tine is high or low.
Do go and spend three days reading Richard Binder's site........or at least an hour reading about nibs.
Your nib is so dirty I can't tell if it has a breather hole. Once you find out if one tine is high or not, with your thumbnail starting at the breather hole or end of slit press the up tine down to under the low tine....hold for two seconds, do that three times and look again at the tip....if you have no loupe nor chance to use one........then write and see if scratchy is gone.
It is a cartridge pen I assume. Buy a rubber bulb syringe. In the bathroom sink, soak up some water in the syringe, stick it on the cartridge piercing spike in the back of the section, and then squish water in and out through the nib and feed, until it runs clean. That could help...won't hurt and you need to do that any time you change ink color....In we are now living in The Golden Age of Inks, you will want to do that often.........lots of fun. ......one color of ink....sounds like boring work.
Paper makes a big difference in scratchy. I have no idea what papers are available in Israel. A Clairefontaine Velout, a good economical paper or Clairefontaine Triomphe or a Rhodia, slick papers.
Waterman ink is a wet ink, and Waterman made a narrower nib and slower feed, to match the ink they make. Do use Waterman ink....Pelikan 4001 is a very dry ink and could make a nib feel scratchier than it is.
If you havn't use it in a couple decades, it could have developed drag.
Once you get back to me, we can talk about that.....but first see if the tines are aligned or not.
If, it needs to be smoothed, I'll teach you the brown paper bag trick.....in you are not ready for smoothing with micro-mesh as a one pen man. Good quality brown paper bags are dirt cheap, and one can last many pens.
It will smooth a nib to good and smooth, and that is good enough.
Lots of BS it must be Butter Smooth.............which needs the dangerous micro-mesh, needs your own 10X loupe and is lots and lots of work. What is gone...is GONE!.............advice is normally have two throw away pens to practice with first.
The basic Brown Paper bag trick,us very much safer & will never reach Butter Smooth, & is two minutes of work, with time in between to scribble to see if it's smooth enough. If one rotates the nib, it is hard to ruin a nib with a brown paper bag.
Professionals are against the brown paper bag, but they are selling 'Butter Smooth'. And one needs experience to use micro-mesh....and lots of time.
Edited by Bo Bo Olson, 23 January 2019 - 19:14.