Chrome Extension Modification And Bug Fixes

So, I have a chrome extension that is used to parse the session cookie. And I would like to modify the extension such that after the session is pasted the cookie that is copied just be removed from the clipboard. And the cookie of the website must also be cleared upon disabling the extension.
The things that are supposed to be done in brief:
Clear cookies upon disabling the extension (not remove, I've done that already)
Remove clipboard text upon clicking on steam. Stream already has a function assigned


Note: You do not have to develop a code or anything. It's simple JavaScript related modification.