I use D’Addario strings. Bronse for aco, nickel for LP. and i’m happy with them now, but 2 years ago these would last only few months. Maybe i got lucky.

But all metal stings get oxidation, and it affects the surface and structure of strings. If it changes, sound does as well.
Grease and acids of human body accelerate those oxidations. If you wipe it out, it helps to keep the mud from forming under the string, but it still keeps oxidizing at fast pace.

What does cleaners do technially is it dissolves the fats and acids, bareing the strings original surface. So strings do became as new. And sounds that way too. To protect strings from oxidation some factories cover them in some coating, or similar techniques, but it’s basically a cover by something like oil. So strings stay new for some time.

WD 40 is a remedy of such type. It first cleans the fat, and the rust. From both surface and cavities. And when it degrades with air, it leaves a layer of mineral oil. It keeps air, water, hard rubbing from metal parts, wich are strings.

Mineral oil is a weaker machine lube than sinthetic, and it goes out faster. So it’s not good for heavy duty friction parts, and it is temporary as it dries out.

So it’s a perfect item for string care. Technically. ANd anyn guitar shop is hundred miles away from my home.

If it gets on bare wood – it still needs TIME to get into wood, so wipe it in 5 seconds, and no stain. I clean fretboard with Vodka. or Scotch.

I start using this thing right now, and will update how it goes.
I’ve put it last night on my bronze strings and now they evened in colour, and smooth to the feel.