Hi Andy,
the bad way is to use nitric acid ,that worke well ,need lots of water flushing to remove all and need brushing to remove the coating ,but this is than very easy . Sometimes formic acid worke allso ,but not with all coatings . I use most a brass brush with stron brass fibers . Allways brush with this in one direction from the wire to the end . It's a slave job ,need time to do .
The acid need time to and brushing . Do not use a flame to heat the wires as the high temp makes the wires very soft and they will break easy by low mechanical stress . At last aske Steve babee he used a coating that allowe to stick the wire bundle in a solderpond of hot liquide solder and the coating will melt and remove itselfe . For some aplication they use this coating but i think not for motors.
By using brass brush with a dremel allways one way and not to hard pressure and taakkee time . You know slave ..... .
Happy Amps Chris