Motion, If you don't have a dishwasher, buy your wife a nice, colorful apron and a case of dishwashing liquid for her birthday.
For the OP, lots of the rotary graters disassemble into three pieces for cleaning, in less time than it took to type this.
For Motion's wife, if you rinse a grater immediately after use, cleaning it takes all of 5 or 6 seconds.
JR