I wanted to know which cleaning fluid can be used to clean electric/ acoustic strings without damaging wood, pickups and finish of the guitar?
One of my friend has recommended me to use nail polish remover instead of WD-40( as WD-40 is a rusting agent). I am now using a dry cotton cloth to clean strings but that is not being enough.

Holy CRAP!
Nail polish remover is Acetone. No No No No No No No.

And NO.

Don't use cleaning fluid to clean strings.

Worst case, use a bit of naptha (available at hardware stores OR as Ronsonol lighter fluid, etc.)

And, as an aside, WD is not a rusting agent -- it actually displaces moisture.

You should be changing your strings often, not trying to preserve them forever.

If you'd like to slow down the rust process, keep your guitar in the case with a VCI (vapor corrosion inhibitor) when you're not actually playing it. Check theruststore.com for examples of VCIs that will fit in the case (they run around $10 and last a year or so). They will not damage any part of your guitar and they'll help your strings last longer.
Last edited by dspellman at Aug 17, 2014,
There is several good string cleaning solutions on sites like Musicians Friend. I personally like the Planet Waves Renew string cleaning system. It's cheap and I use it after every gig (OK, it's actually the next day. I can't get into doing it when I get home at 2:00 from a gig). It's amazing how much stuff comes off of the strings after four sets of playing. I also agree with dspellman that you should change strings often (depending on how much you play). Also do not under any circumstances use Acetone (nail polish remover). Really bad idea. WD 40 will remove rust from strings but if your strings are rusty the metal has been damaged and pitted already. They can't be resurrected. Change them.