Any right-of-way or easement granted under the provisions of RCW 79.110.010 through 79.110.030 which has never been used, or for a period of two years has ceased to be used for the purpose for which it was granted, shall be deemed forfeited. The forfeiture of any such right-of-way previously granted or granted under the provisions of RCW 79.110.010 through 79.110.030, shall be rendered effective by the mailing of a notice of the forfeiture to the grantee at the grantee's last known post office address and by posting a copy of the certificate, or other record of the grant, in the department's Olympia office with the word "canceled" and the date of the cancellation.