Garbage Can Lids ...

These work great for keeping the charcoal going when set on top of a milk crate.  Often areas request "no ground fires" or demos are done in parking lots where you don't want to make a mess.  Also, it's nice (for some people) to not have to bend over so far to work with the charcoal.  Some people have been known to double up the milk crates to put the work area up a little more. ... :-)