Great advice here! My dad did the same thing: applied for a factory job but was told repeatedly that he was overqualified. Kept bugging them until they finally took him on just to shut him up! Within six months he was managing a department.
Perseverance is the key. Try to establish some kind of relationship with a personnel department for a place where you would like to work and let them know, repeatedly, that you'll take any job they have, even if you're overqualified.