Any way to clear "old" players from list in campaign without "kicking"?

If I re-run a campaign, the list of players that have played in the past remain in the dropdown list of players that can control their tokens. This can be a bit confusing when dealing with multiple runs and a number of players. I realize I can "kick" a player from the campaign but that seems a bit overkill since the link has to change (and with a current instance I have, I already have an invite out to players for a campaign) and if they ever want to come back in and play (such as playing again but in Core mode for PFS), I have to remember to somehow specifically invite them.

If you want to leave folks in the campaign then you're going to have to deal with the drop-downs. As far as the software is concerned, they're still playing until you remove them (kick) from the campaign.

Copy your campaign without the players, on the original (the one you sent the invites from) place a forum post with the join link to the new copy. That way the returning players know where to go and you are not stuck with all of the nonplayers on the dropdown.