Heroes only please
Only the Hero can fight. The Hero can be of any level since it makes no difference to the outcome of the battle, just like fighting in the area.
Make sure you remove any armor from your hero before fighting. Armor has no effect on the mimic chest but it will still take damage needlessly.
Bring enough heroes
A successful raid requires minimum three heroes participating. It takes 24 hits to kill a chest and one hero can get at most 11 hits in if they time them right and use a speedup for each one. So two players alone is not enough, four would be better.
Make sure you get “verbal” confirmation from three others before you start or we risk losing the chest. Mimic chests give good rewards so we want to make sure that doesn't happen.
Place it near a portal
Build it as close as you can to an open portal so that all clan members can participate without needing too many speedups.