I was starting for freak out because my elixir was piling high and I had nothing practical to spend it on. My lab was down with wallbreakers, my barracks are either maxed and/or satisfactory (I don't have any need for pekkas and I don't want my barracks down right now anyway), and most of my buildings are in perfect shape (camps maxed, dark storage is more than plentiful plus next upgrade is 2.4mil, gold mines are satisfactory and under boosters anyway). I ended up just blowing it on a dark drill to level 2, which knocked off the booster. But hey, it's only one gem.
I also started my fourth bomb to level 5.