If the public chat in your room has gotten too cluttered, you can declutter it by clearing all messages in it.
When you clear the public chat, all messages from you and from viewers disappear. The only messages that remain are system messages, like tip messages and messages from chatbots.
To clear your public chat:
In the public chat section, click the three vertical dots ⋮ in the upper right
Find the "Clear Chat" line > click the "Clear" button