I don't think Kitty and Graylady advice you to dump the chests you have worked on, MissWilliamston. So do not dump them, and waste your effort on them.
What they are trying to say, I guess, is to dump the one with tasks that you do not like, even with only one of them are the zoo task or else that you do not like. You have the sole power to do everything in your coop.
I've dumped precious and gold chests in addition to wood and iron chests in the previous and this inter-seasonal week, and I've finished 4 precious chests last time, and 2 precious chest (I am waiting for my teammates to finish the last task in each chests).
I take less precious chests and more gold chests this time, and dump some precious and gold, iron, wood chests. The precious chest would show up (I have three at one time, dump one and another one show up after a few dumps....)
So dump them and have no fear! If you don't like the task combination, dump it! You will be getting more pleasing task-chests after the dump.... I'm not joking, really!![]()