There are several ways to do it Dana, you can generate a crowned tile by making a 4 letter word, and once you use the crowned tile in a word it will be activated and destroy one of the mousetraps. They will actually always help with the mission objective, since this level is about bringing the cheese down, it will destroy the mouse traps. 

Line blasters will also destroy the mousetraps if they are caught in the blast, you can generate those by making word 5 letter words long or longer. Good luck!