Yes. Use of duct tape or other material, including a hinged plate cover, is acceptable for rendering the plate illegible if the specification marking is completely, durably, and securely covered. If the cargo tank can be brought into full conformance with the applicable DOT specification at a later date, this method leaves the certification plate intact. If a cargo tank can not be brought into full conformance with the applicable DOT specification, the certification should be removed or rendered permanently illegible.