If the box grater is dishwasher safe, you can put it on the top rack. Mine always comes out perfect.

Also, I agree with @GdD about the brush. Something with moderately short, stiff bristles will work.

In the comments and answers to this related question, What's this "pucker" style hole on my cheese grater for? , it is said to wrap it in cling wrap before use. Supposedly it's easier to collect the contents and when you pull the paper off, the grater is clean.

I haven't tried this, but it may be worth a shot. If/when I try it, and if you do, it would be smart to notice if any plastic comes off into the food.

If the box grater is dishwasher safe, you can put it on the top rack. Mine always comes out perfect.

Also, I agree with @GdD about the brush. Something with moderately short, stiff bristles will work.

In the comments and answers to this related question, What's this "pucker" style hole on my cheese grater for? , it is said to wrap it in cling wrap before use. Supposedly it's easier to collect the contents and when you pull the paper off, the grater is clean.

I haven't tried this, but it may be worth a shot. If/when I try it, and if you do, it would be smart to notice if any plastic comes off into the food.