this is valid, and potentially easier to coordinate than convincing town not to lynch confirmed
The more the merrier! If everyone knows a confirmed mafia, but there's still a mafia left in CC's (or something similar), then today you should go for the CC's instead of confirmed. That sounds counter-intuitive, but let's think it through.
e.g. 1 confirmed mafia revealed by orc, 2 clears, 2 cop claims. it's day.
If you lynch the confirmed today, you're just going to get a clear killed. Having two clears is better than one, because they can discuss things with each other rather than having pressure mount on a single person. So you just lynch the CC's now. Confirmed mafia's either going to try to confuse you (don't fall for it, you already know he's a liar!) or just stay quiet/irrelevant (it's like he's dead or something! just what we want).
Of course, there are always exceptions in mafia; you always should think things through. Here are some things to think about: Can the 2 clears clear the cop somehow (as PR)? Is one of your clears a bad player that might ruin your chances of winning? If the confirmed mafia is a really good player, would it be worth taking him out first?
Having two clears is better than one, because they can discuss things with each other rather than having pressure mount on a single person.