Making a cylindrical object more straight
Hi I have a art object made out of wood (obviously) shaped almost like a cylinder. It's about 36 cm tall and it's diameter is about 6 cm. The wood itself is extremly hard and dark (unfortunately I don't know what kind of wood it is, but I think it's from a root). Now, the problem with this object is that I want it to be able to stand straight on a flat surface, but the bottom is a bit tilted, so the whole object is "sloped" (it looks kind of like The Leaning Tower of Pisa when it's standing). I want to correct this, i.e. make the bottom straight, so that the whole object is standing straight. Now, since it's a art object, I don't want to put in a machine lathe or something, because I'm afraid it might be damaged then. So my question is how would you suggest making the object the way I want it. I.e. what kind of tools would you suggest to use and how - I'm especially wondering how to make it exactly straight - i.e. 90 degrees in relation to the cylinder height. Thanks!