The Scenario
You are an email marketing manager. You have 12 contact lists in Benchmark Email with a combined 8,000 contacts, and in three days you are launching a major re-engagement campaign. Before it goes out, your VP wants one thing: no duplicates.
The problem is that the same contact is almost certainly in multiple lists. People signed up through different forms over different years. Nobody cleaned this. And right now, the only way to find the overlaps is to export each list one by one and try to reconcile them in a spreadsheet by hand.
The slow version:
- Export CSV for list 1, open it in Sheets, paste the email column
- Export CSV for list 2, paste it below
- Repeat for all 12 lists
- Write a COUNTIF to find duplicate emails
- Manually tag each duplicate's source lists
- Build a deduped master list from scratch
- By the time you finish, it is 6 PM and you still have not set up the campaign.
The fast version is one prompt.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent inside your spreadsheet that reads your Benchmark Email lists and builds the flat table for you, so you never have to touch the export button.
Open the SheetXAI sidebar and type:
Export all contacts from each Benchmark Email list ID in column A of my sheet and write contact email, name, list name, and status into a flat table starting in row 2 of the Contacts tab — one row per contact across all lists, deduplicated by email address. Write the total contact count and duplicate count into cells E1 and F1.
SheetXAI calls Benchmark Email for each list ID, joins the results, deduplicates on email, and writes the full roster into the Contacts tab. The duplicate count tells you exactly how many records you would have sent to twice.
What You Get
A single flat table in the Contacts tab:
- Email, name, list name, status — one row per unique contact
- List membership preserved — the list name column shows which list each contact came from first
- Duplicate summary in E1 and F1 — total contacts pulled and how many were removed as duplicates
- Status column — active, unsubscribed, bounced flagged per row so you can filter before sending
The deduplication is by email address, not by name. "Jane Smith" and "Jane M. Smith" who share an email get merged. Two different Janes with different emails do not.
This gives you a clean roster you can actually hand to your ESP or use to configure the campaign audience without a second pass.
What If the Data Is Not Quite Ready
Real contact lists have more mess than a clean 8,000-row export. SheetXAI handles it in the same prompt.
When the list IDs in column A are mixed with blank rows
Not every row in column A is a list ID. Some are blank, some have notes from someone who set up the sheet last year.
Export contacts from each Benchmark Email list ID in column A of my sheet, skipping any blank or non-numeric values. Write results to the Contacts tab, one row per unique contact, deduplicated by email.
When you need to see which contacts appear in three or more lists
The re-engagement campaign should treat high-overlap contacts differently — they are your most subscribed-to segment.
After building the deduped contact table in the Contacts tab, add a column called "List Count" showing how many of the original 12 lists each email appeared in. Sort the table by List Count descending.
When bounced contacts need to be separated before cleanup
You cannot suppress a bounce you cannot see. Before running cleanup, pull the bounced contacts into their own tab.
Export all contacts from Benchmark Email list IDs in column A. Write active and unsubscribed contacts to the Contacts tab. Write bounced contacts to a separate Bounced tab, with email, list name, and status.
When you need the full dedup plus a ready-to-send suppression file
You want the clean master list, and you also want a standalone CSV-style suppression list of every email that appeared more than once, to hand to your deliverability consultant.
Export all contacts from Benchmark Email list IDs in column A. Write a deduplicated master list in the Contacts tab, one row per unique email with all list names collapsed into a "Lists" column separated by commas. In the Suppression tab, write only the emails that appeared in more than one original list, one per row, no header. That is the suppression file.
The pattern: instead of cleaning first and then exporting, you ask for the shape of output you actually need and let SheetXAI do the joins inline.
Try It
Get the 7-day free trial of SheetXAI and open a sheet with your Benchmark Email list IDs in column A, then ask SheetXAI to pull and deduplicate the contacts. The Benchmark Email integration is included in every SheetXAI plan. For related workflows, see how to compare contacts across lists or the Benchmark Email in Google Sheets overview.