mothball (n.)

also moth-ball, moth ball, "naphthalene ball stored among fabrics to keep off moths," 1891, from moth + ball (n.1).

1902 in a literal sense (to store away with mothballs), from mothball (n.); figurative sense "to lay up or disuse for a long time" is from 1901, popularized c. 1946 in U.S. in reference to warships at the end of World War II.