Removing Scriptlink and Text

A simple question:
Is it possible to remove a single scriptlink?

Background Information:
I’ve added a scriptlink to the world (FrameChanged). Let’s call the scriplink ‘test’. I’m aware that I can remove all world scriptlinks, including ‘test’, but is it also possible to only remove ‘test’ and let the others remain in place?

Second question:
Is it possible to remove a specific line or phrase from a textfile?

Background Information:
Let’s say I want to remove the phrase ‘should not be in here’ from the above mentioned test text file, without removing other things that might be in that text file. How should I go about doing this?