I never use Caps Locks and sometimes I activate the key.

A small “googling” help me find how to stop the key to work.

You can do it with:

xmodmap -e "remove lock = Caps_Lock"

If you want to reactivate it with:

xmodmap -e "add lock = Caps_Lock"

The problem with this solution is you have to redo the process for each session

So the better way to do it is to create a file in ~/.Xmodmap and add

remove Lock = Caps_Lock
keycode 66 = Escape

After, to apply immediatly the rule, make a

xmodmap ~/.Xmodmap

At each startup, the ~/.Xmodmap is automatically executed and you never have to care again Caps Locks key