I hate to bring this up amidst all the recent bike thefts. . .

but I actually need to know if someone can get a u-lock off a frame for me. I bought this little Centurion Caveletto at an estate sale in Willow Springs, and it came with ancient u-lock around the frame. I looked through every box in the house for the key, but it wasn't there. Someone in my building tried to get it off with a 24" bolt-cutter, but it barely left a mark. I have no idea how a thief can cut through a  u-lock with a bolt-cutter. Can anyone help me get this thing off so I can ride this bike without doing more damage to what is otherwise a well-preserved paint job? I live in McKinley Park.