root/lang/applescript/read2trash.applescript @ 59

(*
Read to Trash

This is a script moving an marked read messages to a trash box in Mail.app.
This is usable as a rule action.

author: Masafumi Otsune http://www.otsune.com/
*)

using terms from application "Mail"
        on perform mail action with messages theMessages for rule theRule
                tell application "Mail"
                        set max_value to number of items in theMessages
                        repeat with i from 1 to max_value
                                set this_item to item i of theMessages
                                if (read status of this_item) then
                                        delete this_item
                                end if
                        end repeat
                end tell
        end perform mail action with messages
end using terms from