I'm trying to figure out if there is any way to view an old trade that was nullified due to a player having not cleared waivers. The other owner and I agreed to just redo the trade at the start of the next season, but unfortunately we've both forgotten what other players were involved and the trade no longer shows up on the normal trade screen. Is there any way to go back and see the previous trade?

Nope, sorry.

That's a feature that should be made available. I'd recommend sending in a ticket so that WIS can log it, should anyone ever get interested/funded to develop this game further.

FYI, I was able to open a ticket and they provided me with the information.