I've found a couple of places in theme discussions where the advice on how to change the theme included removing certain lines or parts of certain lines from the style.css.
I take it that I can solve the 'remove parts of certain lines' by just including the edited line in the child style.css. (It's not clear that this works, though. I suspect I haven't actually deleted anything by doing this.)
But what do I do in the child style.css to effect the removal of an entire line from the parent style.css? Best practice says I shouldn't just go into the parent style.css and delete or comment out the lines.