Take a bit of pen flush to it.....what goes away, goes away. What stays is going to be mostly hidden by what every ink you have in it..........and it should still show you if it is filled or not.
I'd not go all AR on trying to make an old pen window look new pen clear..........had you wanted that 'really', you could have paid $$ NOS prices for a never inked pen............that might have ambered by sitting anyway.
Those 'dark' ink windows, will show you if you are inked or not easier than the stripped Pelikans (green or tortoise) that have to be held up to the light to see if it's time to refill.
Until this post, I'd not paid much attention to my old '52-54 only made Deluxe MB234 1/2 KOB semi-flex pen's somewhat ambered window. It's an old pen. The ink window is a tad ambered....so what! I can see clearly if I need ink or not...............I need ink..............or to clean it out and put it away.
Red ink is a no no for ink windows................sigh, Purple needs to be cleaned out after every load....in purple is not all that good for ink windows either. One can live with out red ink............that is harder to do with purple. I could see doing a pen flush after every load of Purple ink....just to be safe.
Edited by Bo Bo Olson, 20 May 2017 - 11:01.
www.nibs.com/blog/nibster-writes/nibs-germany Info on Bock nibs
Due to Mauricio's improved definition of Super-flex, I try not use the term Easy Full Flex, but fail...sigh.
Semi-flex is an “almost” flex; not a ‘flex’ nib. It is great for regular writing with a touch of flair. It can give you some fancy; but it is not made for real fancy writing. For bit more of that get a maxi-semi-flex. Both spread tines 3X. Those are not "Flex" nibs.
Wider than Normal does not exist. Wider than Japanese does. Every company has it's very own standard + slop/tolerance. Developed from the users of it's pens and inks only; not the users or inks of other companies pens. The size you grind a nib to, is your standard only. Paper and ink matter to nib width. Thank god for 1/2 sizes or it would be boring.