Help please: How do I kill stale connections

Hi there,
First time post here and I’d be really grateful for some help.
I’m load testing an app on Galaxy Meteor. When I kill some of the clients, the connections seemingly remain (see pic) but with no impact on CPU and memory. My app is showing 54 connections which goes up with normal usage and then drops to 54 again. Been like this for a few hours now

Is there a way I can kill off these phantom connections?

Thanks in advance … Tom