Windshield wiper arms

Fig 1: Identifying Wiper Arm Pressed Downwards Using Plastic Mallet

Courtesy of VOLVO CARS OF NORTH AMERICA.

Remove the protective cover from the nut
Protect the rear edge of the hood and the wiper arm. Use tape for example (as illustrated)
Slacken off the nut for the wiper arm a few turns. Leave the nut in place to protect the threads on the shaft journal
Press the wiper arm downwards. Tap it gently. Use a plastic mallet (as illustrated)
Remove the nut and wiper arm.