How can we...? (Usage of crack, crackle, click, creak, crunch, etc.)

[Sympathy]

What do you call this in English ?

1) How can you describe a person who is pressing, bending their finger joints to make a sound ?
And about the sound of this, how will you call it ? It is a "crack" or a "crackle" or a "click" or a "creak" or a "crunch" ?

2) Let's say our group of students is discussing an issue about education. They have outlined 4 items representing 4 aspects of the issue, but after a while they realize that one aspect belongs to another. They decide to "remove" that item from the discussion. One student say "We must .... this"
How can we say this ? Is "remove" OK to fill in the blank ? Cancel ? Cross out ? I want to know the most commonly used words (spoken language).

Thanks so much

[Mister Micawber]

.
1-- He is cracking his knuckles. Each one is a crack of a knuckle.
2-- The aspect belongs to another what? Another student? Another issue? Are they speaking of the aspect itself ('eliminate') or its written manifestation ('cross out')
.
_________________
Native English teacher at Mister Micawber's

[Sympathy]

I mean two items' discussion overlap.
So is 'eliminate' OK ?

[Mister Micawber]

.
Yes, I 'd use 'eliminate'.
.
_________________
Native English teacher at Mister Micawber's

[Sympathy]

Thank you very much, Mr. Micawber.