Can parts from the old or past competitive arenas be used in our robot?

The official VEX IQ rules state that any VEX IQ part can be used to build the robot. Does this mean that parts from old or past arenas can be used in the robot.

That depends on the part, and whether it is/has been included in a vex kit or hexbug kit. Most pieces have, but not all. To ensure that it is legal, check here: If it’s on the legal parts list, then it can be used.