Hi @Alisha.Prajapat,

Thanks for sharing this question with us.

In terms of list cleaning, I recommend reviewing the lively threads below for more tips and tricks:

And here is our list cleaning documentation from our help center.

With respect to preventing sending duplicate emails if the user exists in both accounts, I recommend implementing a criteria in your segments for the user’s location. You can separate the various territories using “OR”. Also separate the location from the rest of the segment definition using “AND”. Here’s an example using the countries of New Zealand and Australia as the “territories” and is in your Newsletter list:

To better understand how a profile’s location is set, see our documentation here. I hope that information is helpful.