Shaded-pole motors and ceiling fan motors are not the same animal. While both are forms of induction motors they have different starting configurations. Typically, attic ventilator motors and such are shaded-pole devices. As Dan pointed out they can be 2-directional for use in bathroom ventilators, etc. They start via the "shaded" pole and then run synchronously with the mains frequency. OTOH, many ceiling fans have more conventional induction motors with start and run windings. They are of course, reversible and speed control is via switch-stepped values of start capacitance.
Bob Swinney "Stormin Mormon" wrote in message news:hg31im$a4s$ snipped-for-privacy@news.eternal-september.org... I've had some luck, blasting them clean with brake cleaner, and then oil them up.