100,000 mail-in ballots for Massachusetts primary still not returned. "Do not mail," Galvin says.

There's a primary election in Massachusetts next Tuesday, September 1. If you still have a mail-in ballot, don't put it in the mail. That's the advice from the man who's in charge of the state's elections.

Secretary of State Bill Galvin said as of Thursday, there are "well over 100,000 ballots out there" that haven't been sent back yet.

"We strongly recommend, if they are going to vote by mail, do not mail the ballot. It's too late. We can't be sure we're going to receive it. Because this is a primary, all the ballots have to be in the possession of local election officials by 8 o'clock on Tuesday night," Galvin told reporters at a news conference.

If you still have a ballot to send in for the Massachusetts Primary, Galvin said take it to a drop box.

"All communities have drop boxes. Our official website provides you with the information for that. They can take them to an early voting site, at least through tomorrow. Or, they can get them back to city and town halls," he said.

"The point is this. Do not mail, because the possibility of them being not received in time exceeds the likelihood that they will be."

If you prefer to vote in person on Tuesday, the polls open at 7 a.m. in Massachusetts. They will close at 8 p.m.

Voters in both Democratic and Republican primaries will be selecting candidates for the statewide general election on November 3.