working with used yarn

I have an old sweater that I want to “unknit” and use the yarn for a cardigan.
What can I expect?

Welcome to KH!

This video shows you a good way to deal with the kinked yarn from the old sweater. You can do this even if you don’t have the ball winder and swift. It might be good to tie the resulting hank in 4 places though to avoid tangling.