Sanded Maple Neck (Before and After)

Finally, I've decided to sand down my Fender 57 Reissue Stratocaster Made In Japan Since 1993's Poly Vintage Maple Neck. Basically, what I did: I used both sandpaper 1000 & 2000 grit, then wipe down the neck with a cotton rag with hand soap, sand a bit more at the area that still felt sticky to me, then lastly a microfiber cloth with a damp of water and wipe it down completely clean.

I must say, the result turned out great ! Just like what I wanted, a smooth neck. I hesitated a lot before I made this move, but now I have absolute no regret in doing this, since it's probably a guitar I'm not planning on selling in the future, and with a guitar, playability is always more important than appearance, it's not a museum guitar, it's a guitar you want to be able to pick up and play for a long time comfortably. Besides, I think the change in look is not even that noticeable unless you look at it extremely close, even from close view, the real difference I can see is the gloss is gone. What do you guys think? judging from the pics below, is the change in look obvious?

QUESTION
1) Right now my only concern is, I've heard sanded maple neck gets dirty and turns gray very easily. What's a good solution to avoid that from happening? I want it to age well and turn yellowish not gray. I see people tend to use Car Polish or Tung Oil to give it a protection after sanding? should I use one of these as well? But isn't that just going to make the neck sticky again?
2) Is it right that eventually it's going to become glossy and sticky again and I'll have to sand it down again? But usually how long does the sanded smoothness last?
3) The first picture of AFTER, there's a scratch, but I think it was there long before I sanded the neck, it's not from sanding, just wondering, is there any way I could remove that scratch?

BEFORE


AFTER

 

or should I use Naphtha instead of Car Polish or Tung Oil after sanding?