How do you remove the little tab which holds the upper spray arm to the top of the Maytag dishwasher. Do you pry it out or unscrew it. It looks something like a 4-leafed clover. It turns a little but not enough to release the spray arm. The arm movement is clogged by debris but I can't get the arm off to clean it. Bought the house used, no manuals. Darn.