never used the string cleaner but the lemon oil works GREAT. when ever i change strings i treat the fretboard with the Dunlop 65 lemon oil and it really cleans and looks great. I use the Dunlop 65 cleaning kit for my guitars and can't say enough good about it.
String clean is a rip off and Almond oil works a million times better than lemon and is cheaper.

Best thing for cleaning strings is one of those song with the rough side
> http://onbramblehill.com/wp-content/uploads/2010/05/dont_burn_sponges_in_the_microwave.jpg

Rub the (slightly wet) rough side over the strings till you start to see them shine again, then wipe down with the soft side, then run a thin cloth under the strings to pickup any crap thats left on the fingerboard.

As for lemon oil, it is acidic and is not good for the wood, it will clean but also damage. Almond oil on the other hand is a natural cleaning agent in most woods used for fingerboards (Maple, rosewood ect, iv used it on Sapele and Zebrano with good outcomes) and will not harm the wood in any way

It will add moisture into the fretboard also so not much is required and dirt will be removed from every nook and cranny as it soaks in. Iv been cleaning guitars like this for years and iv never had a complaint, its a cheaper, more effective and more healthy way to clean your guitar!
"Lemon" oil guitar products are not actual lemon oils, they're just mineral oils with a lemon scent.

For fretboard conditioning, bore oil works best, it doesn't sit on the wood like mineral/linseed oils do, it actually gets into the pores and hydrates the wood properly.
Not sure if it's considered a string cleaner, but Fast-Fret works great for me. It's a small plastic container with a cotton cloth and a dauber impregnated with mineral oil. It's a no-brainer - wipe down the strings after play, use the dauber to apply the mineral oil and my strings now last a year, instead of 3 weeks to a month. No kidding. I don't work for the company, nor do I own any stock - just a satisifed customer who's not buying strings every time I turn around. The stuff works.
I uses Luthier's Choice Lemon Oil/Fretboard conditioner. Works great, but don't use it on maple fretboards because it will dry them out. Learned that the hard way. For maple, use light fluid or pledge.
Quote by strat0blaster
This is terrible advice. Even worse than the useless dry, sarcastic comment I made.

Quote by Cathbard
I'm too old for the Jim Morrison look now. When I was gigging I had a fine arse.