Basically you need to put this in your console
bind [ "say !spawnblockedmodelslist; wait 1; disconnect; wait 1; reconnect"
In some of the servers it allows certain people who know the command to get models which aren't allowed (by normal players) on the server, mainly the unpopular servers haven't removed the command.
Sometimes when the command is put in it may not work on the first try, you may also need to change "wait 1; reconnect" with "wait 0.001; quit" however this way you have to rejoin the exact same server you were on.
Press [ and done (plus a reconnect)
Thank me