Clarke has detailed West Brom's head of communications John Simpson to compile a selection of suitable reds, to be offered after the game to the Red Devils' boss.
Simpson is going to present the club's head coach with a list from which he will make the final decision before the game.
Clarke said: "I'm well aware that it's Sir Alex's final game and the traditions that accompany it. I've asked John to come up with a couple of alternatives that we can discuss.
"Obviously, my main focus is on winning three points that will see us break the 50-point barrier, finish in eighth and secure our tenth home win of the season.
"But of course, I know that it is a significant day for Sir Alex and Manchester United and afterwards we will try to mark the occasion in appropriate fashion."