To easily charge Crispin's wand, put Mordak's wand on the left platform of the machine then throw the cheese in the machine without putting Crispin's wand on the machine. Eventually the machine will stop and a message will appear, telling you the machine did not do anything. Put Crispin's wand on the right platform of the machine, then walk down the stairs into the next screen. Once done, go back. Crispin's wand should be charged and Mordak's wand weakened.