You can delete, edit, and rename Filters by navigating as follows:
Settings > Preferences > File Operations > Filters.
I wish one delete filters directly as one can do in other applications instead of having to go into preferences. It adds a level of complexity I think is not needed.
I hope they will consider adding this in the main UI. I have seen one or two other comments in this forum about the same thing, so I know I am not alone.