I've used meths. surgical spirits and white spirt for this sort of clean up. Generally they are a bit kinder to existing finishes as well. The trick is to get as much of the surplus off with a spatula first, then a wipe over with kitchen paper wetted with your favourite solvent and then rewipe it with some clean kitchen paper again wetted with solvent to make sure you get any smears off as well. I've done this on polished wooden articles and it works well. Only thing to watch if you're using the quick setting type epoxies, by the time your sure everything you want to stick is in it's right place and isn't going to move the stuff you want to get off is also going to be well on it's way to setting, so make sure all your materials are ready to hand before you start.
As others have said, before the epoxy goes off completely (overnight usually) and is still curing even though it has gelled, you can easily cut the surplus away with a Stanley knife blade or scalpel. It's often the quickest neatest way of cleaning up I find.
Keith