Something

bind msgm - "!db*" db_proc

proc db_list_clean {} {
 # do stuff here
 return 0
}

proc db_proc { nick uhost handle text } {
	if {[lindex $text 1] == "clean"} {
		putquick "PRIVMSG $nick :cleaning the databse"
		set temp [db_list_clean]
		if {!$temp} {
			putquick "PRIVMSG $nick :done"
		} else {
			putquick "PRIVMSG $nick :error"
		}
	}
}

Every time it tries to call db_list_clean, I get this from my eggdrop: Tcl error [db_proc]: missing close-bracket

makes no sense