Pull hoses off engine, one end in a washer fluid jug,funnel stuffed in other hose. Cuppa water then air. I use a rag around blow gun for back spray.
Most effective method so far.
I built a gun that i put water in. Then pull a trigger for air. Reverse directions also.
Jug is to trap what comes out To see what was in core. Its suprising what that core catches.