Is Acetone Really Safe??

I have a Buffalo Nickel that is in excellent condition, without any flattened surfaces and a really nice strike however, it is really dirty. It isn't corrosion, it's just dirt. I am so scared to touch the nickel with anything since I am so new to all this and I was pretty much handed over (inherited) this 2000 coin collection that wasn't well cared for and I've heard everything from mineral oil, to olive oil, to acetone can be used to clean coins but, I'm scared of this one especially getting rejected for grading by NGC. Please someone with experience in this give me some advice! I know with antiques you just leave them be, I have plenty of those. I just don't want the dirt on this coin getting in the way of it's eye appeal.