I realize this is an old thread, but I’m new here so I have some catching up to do!
Sounds like someone painted the bell, bronze does not flake off. If you have not done anything with the bell as of yet you should get it sand-blasted with a glass bead media. This will take the bell back to its original state. Bronze patina is not bad for the bell and will not damage it whatsoever. Patina is just the copper oxidising. Bronze will patina untill it is sealed from the open air, preventing any more oxygen from getting to the metal.

Here is a picture of a bell that has been sand blasted.