I picked up an OMAS Milord (old style cartridge only) here on the marketplace. I generally writes great (best nib I have ever used). But at times, on an upward stroke (m,u,w, etc.) it feels a bit scratchy. But lately, it's getting a bit better (I'm not sure if it's my imagination or not). I am thinking that this could be because the ink from the cartridge is finally lubricating the nib. Anyway, what is this problem that I am experiencing and how do I fix it.

Scratchiness can be cured with some micro mesh sandpaper.Not all but many.That's what i have done with my few nibs requiring it.

Jim