With great trepidation, I fire up the AppleScript Editor. And after staring at the docs far too long again (because every time I look at AS, I go crazy), I came up with this:
-- do this here to get standardaddition value
set trashloc to path to trash
tell application "iTunes"
repeat with pp in (every playlist whose special kind is Podcasts)
repeat with p in (every file track of pp whose played count > 0)
set loc to location of p
tell application "Finder" to move loc to trashloc
which I'm sharing with y'all to save the pain I experienced.