windshield wiper gaskets replacement

I am planning on replacing the gaskets on my windshield wipers this weekend. After briefly looking at them last weekend I wasn't able to figure out how the arms come off the shafts. It looks like there is a clip on the underside of the arm, but I couldn't get it to come off and didn't want to break it by forceing it.

So....can anyone tell me how the arms came off?