What is the rule about magnitizing a piece of VEX metal or using a magnet on the robot? It is not mentioned in the manual, and we were going to use them to stay in the 18" box.
There are no specific rules that prohibit the attempted magnetizing of VEX parts. However, if the magnetized part somehow manages to interfere with the operation of other Robots, it would highly illegal.
There are not VEX legal magnets, thus using a magnet on the Robot is illegal.