B&W Negatives show stripes in homogenuous surfaces

[rabanito]

I scanned some old negatives, dunes in the Sahara.
Through sloppy processing at that time - I guess - there are vertical stripes that are very noticeable on the sand (left hand side) and in the sky
The first picture is the original without much tweaking. The second is with exaggerated tweaking to show the problem better.
Is there any (SW) remedy to this issue?
Thanks in advance for any ideas

[mcbroomf]

I don't have a solution, but are you sure this isn't a problem with the scanner? 
I used to have a Flextight and found on dark even surfaces (like your sky) I would see stripes in the direction of the scan.  It was due to an unevenness in the bulb (this was a new scanner, so not due to aging).  I eventually got new bulbs to fix it.
If you're unsure reverse the neg and rescan it and see if the most prominent stripes flip to the other side of the image.

[rabanito]

If you're unsure reverse the neg and rescan it and see if the most prominent stripes flip to the other side of the image.

Thanks Mike, a good idea.
But looking closely I can see it in the contact copies (wet) 

[mcbroomf]

Yes, nothing to do with the scan then.  Sorry I don't have any idea about a software solution.

[Garnick]

Yes, nothing to do with the scan then.  Sorry I don't have any idea about a software solution.

Hello Mike,

One question.  Can you see any physical signs of these "stripes" on the film itself, either the base or emulsion side?  If so you could try soaking them in warm water for a while and see if you might be able to remove some of the "dirt" with a very wet J-Cloth or some other very smooth sort of cloth.  If that does help, you'll know it can be done, so go from there with the remaining negs.  You will however need to have a place to hang the negs to dry.  Since you probably don't have any sort of wetting solution such as Photo-Flo to use before hanging the negs, you might get a few water spots after drying.  However, that would be much easier to retouch than what you have now.  I know this can work if it is indeed dirt tracks on the film, but perhaps not totally, due to the age of the negs.