All this said, there is (was?) a company that builds a high voltage
pulser to break down the shunts. It was called Lightkeeper, however, I
suspect they are out of business as their web page doesn't work. I
suspect people just didn't bother with this product and just throw out
the string.

I think I saw one of these at Home Depot or Lowes a week or so back. Here's
the website:
http://www.lightkeeper.biz/

Brad