no column with email addresses
Name the column with --column.
available in Email List Cleaner Pro
That option is part of Pro; run without it.
Claude does not use the skill
Check it is switched on in Settings → Capabilities → Skills, then name it in your message.
The script says a column is missing
Rename your header to one of the names in README, or say the mapping in your message.
Code execution is off
Skills with scripts need code execution enabled in Claude.ai settings.
FAQ
Does it check that each mailbox exists? No. It never contacts mail servers. Pro adds a DNS check that the domain can receive mail.
Which file formats work? CSV with commas, semicolons, tabs or pipes, or a text file with one address per line.
What does Pro add? Automatic typo fixing, your suppression and block/allow lists, Gmail dot and +tag duplicates, a DNS mail-server check and merging several lists.