(At least in the Dash-8) This is what some Bombardier pilots showed me that worked as transition pilots for my company is opening up manually the forward outflow valve (On your pressurization panel)
This closes the rear outflow valves and pulls the hot cabin air into the cockpit and so out of the airplane. Also this increases the flow into the cabin from the packs. (The best way for this method of course is with the cockpit door open and this might be a problem for some operators
)
By the way do not shut down your recirc fans this will only reduce the airflow.