I guess I play guitars so much that I end up getting a ton of dirt and grease on my string and fretboard. I need ways to clean this up without buying new strings; I used a moist rag on them and it worked fine, but I'm scarred this will hurt my guitar. so, any tips?
Actually, that's perfectly fine. I do it all the time, and it doesn't seem to harm the strings or the guitar.
What I do is just buy string conditioner and apply it and wipe it off after every time I play. It keeps the strings fresher longer, and also helps avoid the buildup of dirt and **** on the strings. As for a dirty fretboard, all you can really do is take our strings off if you really want to get in there and clean it good. If you have a rosewood/ebony neck, it is good to apply some lem-oil (lemon oil) to it every once and awhile. I do it about every 4-5 months. keeps the fretboard from drying out and cracking.

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Ernie Ball has some good cleaning/conditioning wipes which work pretty well. Make sure you get the underside of the strings as well, theres lots of gunk there.
What you're doing now is just fine. I use a product called Finger-ease. It's a string lubricant that reduces string noise, helps build callouses, and cleans the strings.

Quote by hippieboy444
could I use a rag with some lemon oil on it for my neck and strings?

I wouldnt use lemon oil to clean it. Too much lemon oil is bad for your fretboard. You should only be using lemon oil maybe once every half a year.
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If you want to clean your strings to the point they're just like new, there's two things you can do:

1.) Boil your strings. But make sure you never use the pot you boil them in for cooking again. Ever. After you boil them for a bit, dry them off with cloth and hang 'em out to dry.

2.) Soaking strings in denatured alcohol also gets rid of the gunk. Put the strings in it for a day, and then dry 'em off.