Stock Exhaust -- Remove flame arrestor? Mouse house inside...

[Race30]

Hey Guys,

I bought a new to me phazer, and it has a mouse house inside the muffler area.
I thought i had it beat by using a garden hose to flush the exhaust in reverse, after taking it off, by spraying water from the tip towards the headers.
I got some out, but now that i've run it a few times, the flame arrestor is almost completely plugged up again.
Any suggestions on how to eliminate it? or at least open it up?

 

[Race30]

FIXED:
Got a real long, narrow tipped sawzall blade in there.
Cut it left, right, top, bottom, and was able to use a long screw driver to "peel" those spark arrestor pieces aside so it has a true opening now.
much less boggy
runs great!