How Do I Import and Clean Up My Customer List?
By Bill Stilwell · Last reviewed October 17, 2026
The short answer
Section titled “The short answer”Before you import, confirm you’re allowed to use the contacts for what you plan, back up the original file, and map each column to the right field. After import, merge duplicates, fix bad data, load your do-not-contact list, and write down what you did in an import log. Test with a small batch first.
Why it matters
Section titled “Why it matters”Imports are where clean systems go bad. One wrong column mapping can put phone numbers in the email field for a thousand contacts. A fresh import can bring back people who opted out. A purchased or borrowed list can carry legal risk if you message people who never agreed to hear from you. Fixing a bad import later takes much longer than doing it right once.
15.5.1 Import permission
Section titled “15.5.1 Import permission”What it means: confirming that you may use the records for what you plan.
How to do it: note where each list came from. Your own customers who agreed to hear from you are usually fine for service messages. Lists you bought, got from a partner, or collected for a different purpose may not carry consent for marketing emails, texts, or calls (see 12.6 Communication Consent Records). If you plan marketing, ask an attorney before using a list you didn’t collect yourself.
Common mistake: importing a networking event attendee list and adding everyone to a marketing campaign.
15.5.2 Field mapping
Section titled “15.5.2 Field mapping”What it means: matching each column in the old file to a field in the new system.
How to do it: back up the original file first. Clean column headers, split full names into first and last if needed, and match each column to a field. Map source, consent, and opt-out columns carefully. Import 10 to 20 records first and check them before importing the rest.
Common mistake: importing everything at once and finding the mapping error after.
15.5.3 Duplicates
Section titled “15.5.3 Duplicates”What it means: finding and merging records for the same person.
How to do it: let the import match on email or phone so existing contacts update instead of duplicating. After import, run a duplicate check and merge, keeping notes and history (see 15.3 Contact and Company Records).
Common mistake: creating a second copy of every existing customer.
15.5.4 Invalid data
Section titled “15.5.4 Invalid data”What it means: missing, outdated, or badly formatted information.
How to do it: fix phone formats, remove obvious junk like “test” or “asdf,” fill missing required fields where you can, and mark records you can’t fix. Remove data you don’t need (see 11.6.1 Data Minimization).
Common mistake: importing junk now and planning to “clean it later.”
15.5.5 Consent status
Section titled “15.5.5 Consent status”This line is covered on 12.6 Communication Consent Records. Bring consent and opt-out fields over with every import.
15.5.6 Suppression list
Section titled “15.5.6 Suppression list”What it means: excluding people who should not be contacted.
How to do it: import your do-not-contact list first, or at the same time, and make sure the system marks those contacts as do-not-contact. Check that opt-outs from your old email and texting tools came over too.
Common mistake: an import that switches opted-out people back to “subscribed.”
15.5.7 Import log
Section titled “15.5.7 Import log”What it means: a record of the date, source, person, and changes made.
How to do it: keep a simple log with the date, the file name and where it came from, who did the import, how many records were added, updated, or skipped, and any fixes made. Save the original file with the log in your shared files (see 12.2 Shared Files).
Common mistake: no record of where a batch of contacts came from when someone asks.
When to get help from a pro
Section titled “When to get help from a pro”An attorney can tell you whether a list can be used for marketing. A customer relationship management (CRM) consultant can help with large or messy imports. Questions to ask:
- Can I use this list for marketing emails, texts, or calls?
- How will the import handle existing contacts and opt-outs?
- Can we test a small batch and roll back if something goes wrong?
Bill’s note
Section titled “Bill’s note”[Bill: add a short note. For example, a client import that brought back opted-out contacts, or how you clean a client’s old customer list before review requests.]
How I did this for SiteSmarty
Section titled “How I did this for SiteSmarty”- [Date I did this:]
- [What I actually did, step by step: where the SiteSmarty contacts came from, how I mapped and cleaned them, and the log]
- [What it cost and how long it took:]
- [What surprised me or what I’d do differently:]
- [Screenshot or photo to add, with private info blurred: the mapping screen and import log]
- [Result so far:]
Questions people ask
Section titled “Questions people ask”Can I use an old customer list for marketing? It depends on how you collected it and what they agreed to. Check consent records and ask an attorney if you’re unsure.
How do I map fields? Back up the file, clean the headers, match each column to a field, and test a small batch first.
How do I keep opted-out people from getting messages? Import your do-not-contact list with the contacts and check that every tool respects it.
What should an import log include? Date, file source, who did it, counts added, updated, and skipped, and any fixes.
Audit check
Section titled “Audit check”| Outline line | Question | Pass looks like | Fail looks like | Evidence to collect |
|---|---|---|---|---|
| 15.5.1 Import permission | Was each list’s source and permitted use confirmed? | Source noted, marketing use checked | Unknown or purchased lists used for marketing | Import log and consent notes |
| 15.5.2 Field mapping | Were fields mapped and tested before full import? | Backup kept, small test batch | Mapping errors across records | Mapping screenshot |
| 15.5.3 Duplicates | Were duplicates merged after import? | Duplicate check run | Many duplicates | Duplicate report |
| 15.5.4 Invalid data | Was bad data fixed or marked? | Formats fixed, junk removed | Junk records imported | Sample records |
| 15.5.6 Suppression list | Did opted-out contacts stay opted out? | Suppression list loaded first | Opted-out people resubscribed | Suppression list and status report |
| 15.5.7 Import log | Is there a log for every import? | Date, source, person, counts, fixes | No log | Import log |
Where this fits
Do this first: 15.4 CRM Custom Fields and Tags, 12.6 Communication Consent Records
Do this next: 15.6 Customer Lifecycle Stages
Related pages: 15.3 Contact and Company Records, 11.6.1 Data Minimization, 11.8 Business Backups, 18.3 Email Marketing Rules, 18.4 Text Message Marketing Rules
Sources
- Federal Trade Commission, "CAN-SPAM Act: A Compliance Guide for Business" (checked October 17, 2026)
- Electronic Code of Federal Regulations, 47 CFR 64.1200, Delivery restrictions (checked October 17, 2026)
- Federal Trade Commission, "Protecting Personal Information: A Guide for Business" (checked October 17, 2026)
This page explains general rules and Bill's own experience. It is not legal, tax, or insurance advice. Talk to a qualified professional about your situation.