"Storage" and "use" do not include the keeping, retaining or exercising any right or power over tangible personal property for the purpose of subsequently transporting it outside the state for use thereafter solely outside the state, or for the purpose of being processed, fabricated, or manufactured into, attached to or incorporated into, other tangible personal property to be transported outside the state and thereafter used solely outside the state.
Ca. Rev. and Tax. Code § 6009.1