This is the same problem I am having. I see that someone had a posting on this already and I am not sure if he solved it

"I read on the Joomla website that it was possible to disable history in the chat rooms, so that everytime you entered, it would be blank.
I can't find anywhere in the configuration to do this though.
Can someone advise please.
thanks"

I have looked EVERYWHERE and can't find the "I implemented following:
You can now set "Last message only", when new user joins room, he will see only last message."

PLEASE HELP - What am I missing???????

Thanks for a great service - I am really digging it so far!! I won't ask cause I think I know..the "clear history" feature is coming soon ?

If you already did set your SuperAdmin, and you entered chat as SuperAdmin, replace step 1 and 2 with: enter chat from your website and click "Admin" menu.

1. go to www.blastchat.com
2. click "Your registration"
3. click your website name
4. clicks "Rooms"
5. click your room to edit
6. set "Start empty" to yes

Thank you so much! I must have just missed it! It's nice to know that each chat room can have different features as you are setting them up. I have to complement you on this service and let you know how refreshing it is to have someone actually respond to a post no matter how silly it is. I can't tell you you many posts have gone unanswered! THANK YOUUUUUUUUUUUUUUUU for this amazing product with even BETTER support forum!

Kurt

thank you and you are welcome, have your website visitors enjoy chatting