The clip isnt on the airfilter box its on the pipe below it that you ahve to take off to get the new filter in. Theres a guide in the guides section. You dont necessarily have to replace the clips but it makes it easier for next time. You can remove the clips easily with a pair of circlip pliers but if you dont have those you can pry it off with a screwdriver and refit it with a pair of pointy nose pliers but its not easy.