Stock 235 - 1954 - Just Rebuilt and in place

I accidently dropped a washer (the distributor mounting washer - about 3/4" in diameter) into the distributor hole. Of course it dropped thru ALL the way when I tried to fish it out.

I assume it's resting happily in my oil pan. I believe it's a little to large to pass thru the oil plug hole.

Is this dangerous to leave in the engine? Should I put a strong magnet on the bottom of the oil pan to hold the washer (and other bits of metal) in place.

Thanks in advance!