How do I clean a calling list before a bulk campaign?
Clean a calling list by standardising every number to a 10-digit Indian mobile format, removing duplicates and invalid numbers, removing anyone who has opted out or been marked wrong number before, screening against DND, and adding the columns the agent needs — name, language and the reason for calling. Then test on a small slice before calling the whole list.
Step by step
- 01Standardise numbers: strip spaces, dashes, leading zeros and +91 variations into one consistent format.
- 02Remove invalid numbers: Indian mobile numbers are 10 digits and start with 6, 7, 8 or 9. Landlines need separate handling.
- 03Remove duplicates by phone number, keeping the most recent record.
- 04Remove opt-outs, wrong numbers and ‘do not call’ flags from earlier campaigns and from your CRM.
- 05Screen the list against DND.
- 06Add context columns the agent will use.
- 07Split by language or region if your list is mixed.
Columns worth adding
| Column | Example | How the agent uses it |
|---|---|---|
| Name | Lakshmi | Greets the person by name |
| Language | Telugu | Opens in the right language |
| Reason for call | Enquired about 3BHK in Kokapet | Makes the first line specific |
| Last interaction | Site visit on 14 Sept | Picks up the thread |
| Due date or amount | EMI ₹8,450 due 10 Oct | For reminder calls |
Why it matters
Duplicates mean people get called twice in a day and report the number. Invalid numbers waste campaign time. Missing context forces a generic opening line, which is the biggest single reason people hang up. Ten minutes in a spreadsheet saves all three.
Check old lists before using them
Lists older than a year carry recycled numbers — the number may now belong to someone else entirely. Treat old lists as low-intent, call them with a gentler opener, and expect more wrong-person answers.
Bulk campaigns take an uploaded CSV, with scheduling, calling windows, retries and DND screening built in. Extra columns can be used in the agent's script so each call opens with the person's name and the real reason for calling.
Want to hear an AI voice agent handle this on a real call?