How to clear console in sublime text editor

I assume you're talking about the console accessible via View -> Show Console or Ctrl`. Unlike other answers on SO, which deal with clearing the Python console when opened from the command prompt, os.system("cls") or os.system("clear") (depending on your OS) don't work with the Sublime console. The Sublime API (version 2 or version 3) does not have any built-in console-clearing method, and I was unable to find any undocumented method in sublime.py or sublime_plugin.py. The console appears to be read-only, as selecting all the text and hitting Delete doesn't work either.

I've been looking into this for some time, and I've come to the conclusion that it does not appear to be possible. However, there is a hackish workaround - just run print('\n'*100) to print 100 newline characters, and you won't be able to see any of the previous output unless you scroll up some distance.

I installed ClearConsole package, then type alt+k to clear then console.

A new window will always have a clean console. You can use this to open a new window, close the old one and then reopen your project (assuming it is a saved project and not anonymous). This requires the hot_exit setting to be true, which is the default.