From the page:
It lists caches that you have found on the first day that someone else found it on, and that are not listed as FTF at Project-GC
So it's following a set of rules but there isn't the functionality to remove them from that list.
Maybe something can be introduced similar to the Challenge caches tab where caches can be excluded by adding '[NOT-SIGNED]' to the log, e.g. '[NOT-FTF]', rather than cluttering up cache listings with 'I wasn't FTF' bookmark lists.