Hi, me again...
I've been using the three-way colour corrector in my project, but I've ended up with clips with a whole bunch of tabs of three-way colour correctors loaded on the same shot as I've been trying different things, dragging settings from one shot to another, and I don't know how to delete the many three-way colour correctors that I'm not using to just leave the one I am using on the shot. Do I need to 'remove attributes' and start afresh or is there another way? Thanks!

Double click the clip on the timeline to open it in the viewer window
In the Viewer window, click the Filters tab
Observe the plethora of filters you have put on the clip and notice which ones are enable (checkbox)
Disable the ones you don't want and observe the effect on your image (these things add together and the order matters)
If you still like the results, the click the filter and press delete to remove it.
If you don't like it, change the filters you left enabled to get the effect you want. then delete the extras.

Thanks! Got it.