Del. Code tit. 30, § 5225

This chapter shall not apply to motor vehicles bearing the registration plates of any other state which does not impose a tax, license or fee upon motor vehicles bearing valid registration plates of this State. The Secretary of Transportation is authorized to make reciprocal agreements with the proper officials of any other state imposing any such tax, license or fee providing for the reduction or relief from the tax imposed by this chapter, upon motor vehicles bearing valid registration plates of such other state, in exchange for the reduction or relief from the tax, license or fee imposed by such other state upon motor vehicles bearing valid registration plates of this State.