Hot soapy water and a lot of elbow grease is the best way to do this. You can probably get the worst off with a pressure washer but you'll need a toothbrush to get those hard to reach parts. Muc Off works well, but don't leave it on the rubber to long and make sure you use a rubber treatment gel afterwards. Once you're done, give the car a proper wax and polish and it should hopefully reduce the chances of the green stuff returning.