Aluminum is just being wasteful honestly. Not sure how clean you're expecting, but this does a fine job at getting all the big chunks off (which is what you want). Heat will nuke the rest of it.
Depends on what you're cleaning it for. Some people are paranoid that the bits of carbon left clinging to the rails are known to the state of California to cause cancer and must be completely removed before it is safe to heat food.
Or you can be like me and just get the grill hot and give it a quick once over with a metal spatula to remove any chunks that are sticking up. I mean I'm cooking over an open flame here, it's already carcinogen city.
