The Board of Election Commissioners on its own initiative, or upon order of the circuit court, shall at all times have authority to conduct investigations and to make canvasses of the registered voters in any precinct or precincts within its jurisdiction either by the methods provided in this Article or at other times and by other methods than those prescribed herein. However, the Board of Election Commissioners shall, at least once in every 2 years, conduct a verification of voter registrations and shall cause the cancellation of registration of persons who have ceased to be qualified voters. Such verification shall be accomplished by one of the following methods: (1) precinct canvass conducted by 2 qualified persons of opposite party affiliation appointed by the Board of Election Commissioners or (2) written request sent to each registered voter by first class mail, not forwardable or (3) an alternative method of verification submitted in writing to and approved by The State Board of Elections at a public meeting not less than 60 days prior to the date on which the Board of Election Commissioners has fixed for implementation of that method of verification; provided, said Board shall submit to the State Board of Elections a written statement of the results obtained by use of such alternative method within 30 days of the completion of the verification. If, upon the basis of investigations or canvasses, the board shall be of the opinion that any person registered under this Article is not a qualified voter or has ceased to be a qualified voter, it shall send a notice through the United States mail to such person, requiring him to appear before such board at a time specified in such notice, not less than 10 nor more than 30 days after the mailing of such notice and show cause why his registration should not be cancelled. If such a person does not appear, his registration shall be cancelled. If such a person does appear he shall make an affidavit and shall be heard in the manner provided by Section 6-45 of this Article, and if his registration is cancelled as a result of such a hearing, he shall be entitled to a hearing in the circuit court and to an appeal to the Supreme Court in the manner provided by Section 6-52 of this Article.
     Whenever the Board of Election Commissioners acting under authority of this section conducts a canvass of the registered voters in any precinct or precincts and the board designates canvassers to conduct the canvass, the board shall appoint as canvassers persons affiliated with the leading political parties in like manner as judges of election are appointed under the provisions of Section 14-4 of this Act; provided that in each precinct in counties of 500,000 inhabitants or more, one canvasser may be appointed from outside such precinct if not enough other qualified persons who reside within the precinct can be found to serve as canvasser in such precinct. The one canvasser so appointed to serve in any precinct in which he is not entitled to vote prior to the election must be entitled to vote elsewhere within the ward or township which includes within its boundaries the precinct in which such canvasser is appointed and such canvasser must be otherwise qualified.
     The canvassers, so appointed by virtue of this section, shall comply with the provisions of Sections 6-40 and 6-41 relative to the mailing and leaving of notices at the addresses of persons whose right to vote in the precinct or precincts is questioned.