Can we ask why you'd want to do such a thing?
Not out of a sense of horror, or anything as flakey as that - but is there an aesthic reason?
If it's the case that you simply prefer a plain bell (as I do) then there's no way to remove the engraving without levelling the metal...and from a structural point of view alone that wouldn't be a good idea.
If you just don't like the engraving but have no other preferences, you could have it recut. Obviously you can't just 'walk' over what's already there, but you could have it 'enhanced'...rather like a bad tattoo can be disguised (to follow on from Dr G's analogy).