I'm restringing and cleaning my guitar atm. I've just removed the strings and am going to give it a clean over. I don't have any lemon oil or any proper guitar cleaning chemicals so can i use furniture polish or something?
I would say stay away from any cleaning agent which contains silicon, it'll leave a blur in the finish that you will really regret. In general I think it's best you use available guitar polishes available on the market. Your guitar is not a piece of furniture neither is it a car. It's a guitar use some guitar polisih.
This is especially important when you think about the finishes used on guitars, poly, nitro, french polish. Especially for delicate finishes like nitro.
When in doubt I listen to my tech and use mouth mist, aka saliva. It's the best, even Dan Erlewine swears by this.
Lemon oil is pretty good on fretboards as well, but those available in your local hardware stores are usually developed for furniture. If you're using a neck with dark woods, like rosewood or ebony, go get some tung oil.
ITS BY FAR THE BEST I KID YOU NOT!
Maestro Guitars in peninsula has them for sale. Don't go overboard and flood the whole fretboard, just a little will go a long way.