Originally Posted by Goodweed of the North
The easiest method I know is still to place a bowl of amonia into a large plastic bag along with the grates. Close the bag and seal with string, or whatever. Leave overnight. Next day, untie the bag, remove the grates, wipe off with a damp paper towel. Your grates will look like new, without a lot of elbow-grease.
Seeeeeya; Goodweed of the North
A chef once said that it's best to clean cooking surfaces with something compatible with food, like lemon juice. He used a 50/50 solution of lemon juice and water to clean his grill (it was a Japanese steakhouse grill though). Just a thought.