Can you delete the chat only certain post-not everything written.

Can you delete the chat only certain post-not everything written.???

When you write this command. 
/clear
/cls
disappears anything written in the chat.I want to be able to rub only certain posts.

If you are talking about the chatbox, sorry, I do not believe there is any way to clear certain messages.
If people are misbehaving on your forum, you can chatban them using:
/banusername 
Write the user's name in "username"
The people won't be able to chat in your chatbox anymore.

are you sure.?

Sadly removing specific chat posts isn't available within the basic Forumotion Chatbox.

thank you