Evening Cider Fans, should I clean the neck of my demijohn, bung and airlock?!?

[u/Honest-Tourist-5949]

Two of my demijohns have got a build up of and goop as pictured. I’m a n00b, should I remove the bung and airlock and clean this all out?

[u/SimonOmega → u/[deleted]]

But make sure that the airlock has a proper amount of liquid in it.