Used only for purchasing construction and building materials for tax-exempt organization projects. This license is issued only to the General Contractor. Sub-contractors must obtain a copy of the certificate from the General Contractor. For contractors who do not need a sales tax license, trade name registration and renewal are handled by the Colorado Secretary of State Business Center. To receive an exemption certificate for construction contracts with tax exempt organizations use the Contractor Application for Exemption Certificate (DR 0172). No fee is required for this exemption certificate. Blanket certificates will not be issued for continuous building maintenance and other non-construction projects.