I used a stiff gasket remover knife and went along the edge of the vertical lip and "cut" it free from that edge. Then I came in flush with the roof panel and basically cut it out in large chuncks. After I got most of it out, I came back in with a twisted wire wheel disc (not the cup style) and removed the left over. Make sure you have a full face shield when doing this. Overall wasn't very hard or time consuming... unlike stripping the old paint off.
