Cedarwood was also used in some ceremonies for purification. Egyptians also embraced cedarwood, and used it in the mummification process, cosmetics, and to repel insects. Insects and rats hate the smell of cedarwood, therefore it makes a great repellent, especially against mosquitoes, moths, and woodworms.edarwood was also used in some ceremonies for purification. Egyptians also embraced cedarwood, and used it in the mummification process, cosmetics, and to repel insects. Insects and rats hate the smell of cedarwood, therefore it makes a great repellent, especially against mosquitoes, moths, and woodworms.