Might try taking the coil wire off and trying to crank it out the exhaust valve without starting the engine.

Once sucked a carb mounting nut into the intake and didn't know it until I started the motor. Loud knocking for sure. I was quite a ways from home so I just finished my business and started home. After about 75 miles the knock went away. Kept an eye on the oil pressure and water temp. No problems. When I pulled the heads (305 V6) I found the nut nicely melted into the top of a piston.

I personally would not be too concerned about starting the motor and letting it melt away. JMO

Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
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USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)