Board Thread:Questions and Answers/@comment-26581304-20151215232602/@comment-24577221-20151230221424

Another way of getting rid of the high-level monsters is to sell them, of course.

To get more diamonds, you can try answering a few surveys in the "free diamonds!" offers. The surveys seem to be tired of me, though; lately I've just been getting "you're not qualified for any" messages. But they did pay for a few extra structures.