The Scopus List provides a spreadsheet file in which dropped journals are highlighted.
https://www.elsevier.com/?a=91122
In contrast, the Thomson Reuters list can be accessed through a search box (link below) which is based on recent data, thus previous lists cannot be accessed backwards. Although a "Journal Changes" section is provided which shows recently added and dropped journals yet it only displays the changes for the past 12 months.
http://mjl.clarivate.com/
So my real question is this:
How can I prove that a journal I have published in was part of the Thomson Reuters list at the time of publication yet was dropped (taken off the list) just recently?