The government makes you re-up your passport every ten years, why not require voters to re-up every ten years, which includes proof of citizenship.
The best way to eliminate the vote rolls in the most efficient way is by sending a copy of the death certificate to the County Elections Clerk and to the Elections Department within the state.
The County is notified by the hospitals, (creamatorium or funeral homes in case they do not get pronounced dead at the hospital) in the area, when a death occurs.
If the person lived outside the state, send it to the state he was living in.
This will help clean off the voter rolls on a regular basis.