Me too! LOL
There is one difference though, I chose to include all individuals rather than exclude as the other poster suggested. I like using the "include" option, because it showed my main tree and all the lost island trees. I only have about 2600 people in my tree so it was easier for me to visually see the orphans in relation to the main line.
I was pleasantly surprised to see that even if I started with my daughter to capture her father and my lines, it included my second husband's family as a related line without breaking it off. YES! That was a great fear for me as I didn't want to lose all the data on his line. The relationship calculator includes all of his family as "stepfather's blah blah blah" :-)
Every single island tree that popped up on the chart was unrelated. I did choose to keep a few, on the chance that a connection might be made down the road.
Then, I was able to "clt" click each person inside orphaned trees to select them, and choose "deleted selected" to remove them from my database.