With the clipart image selected, perform a trace by going to the Property Bar and select Trace Bitmap. From the dropdown, you can select which type of tracing works best for the image. It might take some experimentation to find the best type of tracing to do on your specific image as each image can trace differently. Once the trace is complete and the clipart has been refined to a set of vectors, these need to be ungrouped (CTRL+U). Once ungrouped, select the individual pieces (including the background pieces) and either simply delete them or edit the shape and color. If needed, re-group the objects once the background is removed to make it easier to move the image.
—Lisa Ellston, JDS Industries