The problem with free/public teamspeak servers is you have no control over who can enter and what they can do. Some random guy, or rival clan or even a salty ex-member can find it and start posting nasty links. Unless you have admin on that server then there is nothing you can do about it.
Best advice? Avoid free ones. Renting a hosted server is so cheap it's almost not worth using free ones anyway.
As for advertising your clan's teamspeak on clan forums; while I am in no way encouraging you to do it, or saying that I do it, unless it's reported by one of your members I don't think Jagex is going to do anything about it.
22-Jun-2016 17:45:58