Originally Posted By: tanstaafl.
..used a vacuum cleaner to suck the end of the thread out of the exit hole


That's a pretty standard technique for fishing wires through conduit. We used it here to suck a pull string through the 130' of 3/4" plastic pipe used for the street-to-home cable internet conduit. I have my doubts about it working in a larger space like a stud wall cavity though.

Cheers