"He would have his operatives fan out, going house-to-house, convincing voters to let them mail completed ballots on their behalf as a public service."

"The fraudster and his minions would then take the sealed envelopes home and hold them over boiling water. 'You have to steam it to loosen the glue,' said the insider. He then would remove the real ballot, place the counterfeit ballot inside the signed certificate, and reseal the envelope. 'Five minutes per ballot tops,' said the insider. The insider said he took care not to stuff the fake ballots into just a few public mailboxes, but sprinkle them around town. That way he avoided the attention that foiled a sloppy voter-fraud operation in a Paterson, NJ city council race this year, where 900 ballots were found in just three mailboxes. 'If they had spread them in all different mailboxes, nothing would have happened,' the insider said. The tipster said sometimes postal employees are in on the scam. 'You have a postman who is a rabid anti-Trump guy and he’s working in Bedminster or some Republican stronghold … He can take those [filled-out] ballots, and knowing 95% are going to a Republican, he can just throw those in the garbage.'"

From "Confessions of a voter fraud: I was a master at fixing mail-in ballots" (NY Post).