1. Verify Fax Numbers Are Active and Correct
Use fax verification services or tools that ping fax numbers to confirm they're live.
Remove disconnected, wrong, or non-fax numbers.
Check formatting for fax lists consistency (country codes, area codes).
2. Filter by Industry and Job Title
Target only those who fit your ideal client profile.
Exclude irrelevant industries or non-decision makers.
Use data fields like:
Business type (e.g., healthcare provider, law firm)
Job title (e.g., office manager, doctor, purchasing agent)
Remove generic or personal fax lines unlikely to result in business leads.
3. Remove Duplicates and Invalid Entries
De-duplicate fax numbers to avoid sending multiple faxes.
Clean up incomplete or malformed entries (missing area codes, names).
4. Check for Opt-Outs or Do-Not-Fax Lists
Respect opt-out requests to avoid legal problems.
Scrub your list against industry or government do-not-fax registries where available.
5. Use Data Hygiene Tools
Utilize data cleaning services that append or verify business information.
Update company status to remove closed or bankrupt businesses.
6. Segment Leads by Engagement or Relationship
If you have historical data, prioritize leads with prior interaction or positive responses.
Lower priority to cold leads or those who never engaged.
7. Cross-Reference With Reliable Sources
Cross-check leads against trusted databases or directories.
Validate business existence and contact details.
Tools & Services to Help
Fax verification tools: FaxOverIP, RingCentral Fax, or industry-specific verification vendors
Data cleaning services: Experian Data Quality, ZoomInfo, Clearbit
CRM integration: Use CRM tools to flag and filter leads based on interaction history
Why Filtering Matters
Improves ROI: Focus on leads with a higher chance of conversion.
Reduces costs: Cut fax transmission costs on dead ends.
Protects compliance: Avoid sending faxes to those who opted out.
Protects reputation: Avoid annoying irrelevant recipients.