The invention relates to a method for cleaning carbon nanotubes comprising the following steps: provision of a carbon nanotube substrate, first washing of the carbon nanotube substrate by means of an acid and second washing of the carbon nanotube substrate by means of a solution, wherein the solution has replacement anions of at least one of the acid radical anions of the acid of different type, and the substance amount fraction of the replacement anions in the solution is greater than the substance amount fraction of the anions in the solution corresponding to the acid radical anions of the acid. The invention further relates to a carbon nanotube substrate which can be obtained by such a method.