Last night, I applied some lemon oil from Petro with paper towel and the paper towel turned all brown and black?? Did I damage my guitar's board? I am afraid I take some wood out of my guitar..?

How often do you clean your Colling's fingerboard? What method do you use? Do fingerboard needed Lemon Oils to prevent from trying out?

Many recomment using 0000 steelwool to clean the board and than to apply Lemon oil every few months.. I didn't use steelwool but use the lemon oil to clean the board...is it appropriate?

I use Petros Fingerboard Oil. Only once so far, but it seems to work well.

Caress your fingerboard with your fingers daily. That's most of the care it needs. I wipe mine off when I change strings. If it's really grimy I use a little clean water. Once every few years the grime might build up to the point where it needs more than this. Then a little 0000 steel wool will work nicely.

About oil. I'm not an expert but there does seem to be a lot of different opinions. From my experience with many, many guitars from my time in a guitar shop, and my on guitars, (I've owned my HD-28 for 24 years and a '58 00-18 for 22 years, Not to mention the others, there are and have been many others), you probably don't need to oil the fingerboard at all. I have and do oil them, but not very darn often. I know I let the HD-28 and the 00-18 go without for close to 20 years. I was playing electric more and also doing other things like getting married and having a kid, so I just never even thought about oiling the boards. They did fine. In Colorado with no humidifier (I use one now, I didn't until a few years ago) the guitars never cracked, warped, nor did the fingerboards ever look dried out. I've also heard many say use lemon oil and other say that the lemon oil you can buy is mostly petroleum distillates and you should use boiled linseed oil. Linseed oil looks, smells and feels more like finishing oil than does any of the lemon oil I've seen. Anyway, I have both here in my workshop but rarely use either. When I do use them, either one seems to give me a nice clean looking fingerboard once I get up all the excess. I hate to feel the oil when I play. I want it clean and dry.

The brown that came off on your cloth was probably dirt and crap from your fingers and the air mixed with some of the old finish that’s on the board. Some boards also have stain along with whatever oil may have been applied by the builder. The new oil probably just dissolved some of this gunk. I don’t think you were wiping any wood off. Steel wool will only buff off a microscopically small amount, your paper towel is not removing any.

Ed, i understand that beside cleaning, lemon oil is also meant for 'moisturising', esp in dry climate. I realised that both our countries hv all year high humidity, so use of lemon oile may juz not be apprioriate. What u can do is to use 0000 scrotchbite fm 3M, thats a good cleaning stuff.

My understanding is that the fingerboard should not be oiled and that lemon oil is potentially detrimental to the fingerboard due to its acidity. Oil can eventually soften the fingerboard wood, even ebony. Certainly there is oil from your fingers. Adequate humidification is all that is necessary to maintain the fingerboard. I use 0000 steel wool to clean my fingerboards when I change strings (yes, by removing all the strings at once).

I used the Petros Fingerboard Oil on my SJ and probably put too many drops on it. I wiped it off, but it also soaked up under the frets... Months later, and I do mean months... after a dry winter.... the oil that soaked up under the frets ekked out onto the fretboard and now certain frets look like the ebony around it is darker. Opps! I'm sure it will come off, but I haven't tried to remove it yet. Perhaps the ebony soaked up the oil? I don't know, but I certainly will not put any more oil on that fretboard. I have used the oil since on other guitars, but only really sparringly. just enough to wet the fretboard. A little goes a long way.

Ed:
rather too little than too much. Remember that any liquid absorbed by the fingerboard will cause microscopic swelling, so you don't ever want to add more than might have naturally evaporated out, which is very little.
In a sense, you are oiling it slightly when you play, especially if your fingers tend to be sweaty, which I think I remember you saying they do.
I would use a tiny amount on the tip of a rag, just to clean, about once every year or two. Plus I usually wash my hands before playing to extend the string life. (This naturally helps keep the fingerboard clean, too, of course. Especially if you smoke.)
As Kenny pointed out, whatever you put there, stays there, and accumulates. Oil doesn't evaporate like water does.