Did the worst thing last weekend, opened my bonnet whilst the wipers were up, as i was cleaning it :(

Clean snapped the wiper arm off the passenger side, leaving a small piece left, on the connector to the car.

Ive popped the little circle cover off, and undone the bolt, but the wiper is so stiff, i dont want to force it, ruining the motor.

How do i go about taking the remaining piece of the arm off...?

Try WD40 and jigging it about for a while and it should pop off.

Done this to mine and with a little patients they come off eventually.

Or if it's that bad take it to local garage, they should have a proper tool to prise it off.

Buy a puller from Machine Mart.