Neb. Rev. Stat. § 52-201

(1) Any person who makes, alters, repairs, or in any way enhances the value of any vehicle, automobile, machinery, farm implement, or tool or shoes a horse or mule at the request of or with the consent of the owner or owners thereof shall have a lien on such vehicle, automobile, machinery, farm implement, tool, horse, or mule while in such person's possession for the reasonable or agreed charges for the work done or material furnished and shall have the right to retain such property until such charges are paid. (2) Any person who exercises the right to retain such property shall not assess any additional fee beyond the reasonable or agreed charges for the work done or material furnished unless the person first sends, by certified mail, (a) a notice of possession of such property, intent to assess an additional reasonable fee beginning with the date that the notice is sent, and the amount or rate of the additional reasonable fee to the owner or owners for whom the work was performed and (b) a copy of such notice to any lienholder noted on the certificate of title if applicable.