---
title: "Lead Lists Claude Skill: Clean, Verify and Import"
description: "A Claude skill that gets a lead list ready before it touches an inbox: free B2B lists, CSV cleaning, combining, suppression, verification and sequencer import."
url: https://warminboxes.com/skills/lead-lists
breadcrumb: "Home > Claude Skills > Lead Lists"
---
Claude skill

# Lead Lists

Is this list ready to send to?

A bad list is the cheapest problem to fix and the most expensive to ignore, because its bounces and spam reports land on the sender. This finds a free list if you need one, then cleans, suppresses, verifies, segments and converts it in that order, and counts what changed at every step.

## What it runs

- **Free B2B lists** — The WarmInboxes catalogue, searched by industry, role or region

- **Cleaning** — Duplicates, invalid rows, role addresses and formatting

- **Combining** — Several files into one, de-duplicated

- **Suppression** — Unsubscribes, customers and past bounces removed

- **Verification** — Addresses checked, and a waterfall planned across verifiers for an old or large list

- **Sequencer format** — Converted for Instantly, Smartlead and the others, last

## What you get back

- Rows in, rows removed by reason, rows out, at each step

- Unknown where a verifier could not decide an address, never a guess

- A flag when most of a list sits behind security gateways, which is a list problem, not an infrastructure one

- The file in your sequencer’s format, or the page that processes a large one in your browser

## Install it

Best installed with the plugin, which also connects WarmInboxes Free MCP, the tools this skill runs. On its own it is one file that falls back to the free WarmInboxes API, so there is no key and nothing to sign up for.

 /plugin marketplace add Huz-ai-fa/warminboxes-claude-skills
/plugin install warminboxes@warminboxes

Or this one skill on its own:

 mkdir -p ~/.claude/skills/lead-lists
curl -sL https://raw.githubusercontent.com/Huz-ai-fa/warminboxes-claude-skills/main/lead-lists/SKILL.md -o ~/.claude/skills/lead-lists/SKILL.md

[View it on GitHub →](https://github.com/Huz-ai-fa/warminboxes-claude-skills/tree/main/lead-lists)

## Then just ask

You do not name the skill. Its description tells Claude when it applies.

- "Clean this CSV before I import it into Instantly"

- "Find me a free list of SaaS founders in the UK"

- "Remove everyone on my do-not-contact list from this file"

Every answer cites the check behind it, so anything Claude tells you can be re-run by hand. A clean result is reported clean, with nothing to buy.

[All Claude skills →](https://warminboxes.com/skills)

## Do it by hand

The same checks as free tools in a browser.

- [CSV List Cleaner](https://warminboxes.com/csv-cleaner)

- [Suppression Checker](https://warminboxes.com/suppression-checker)

- [Waterfall Calculator](https://warminboxes.com/waterfall-calculator)

- [Sequencer CSV Converter](https://warminboxes.com/sequencer-csv-converter)

## The other skills

One page each.

- [Inbox Checker](https://warminboxes.com/skills/inbox-checker) — Is this domain burned?

- [Domain Audit](https://warminboxes.com/skills/domain-audit) — Is this domain set up correctly to send from?

- [List Segmentation](https://warminboxes.com/skills/list-segmentation) — Who hosts the people on this list?

- [Infrastructure Planner](https://warminboxes.com/skills/infrastructure-planner) — How many mailboxes do I need, and what does it cost?

- [Bounce Diagnosis](https://warminboxes.com/skills/bounce-diagnosis) — What do these bounces mean, and is it the list or me?

- [Cold Email Copy](https://warminboxes.com/skills/cold-email-copy) — Is this email going to land in spam?

- [Warm Rotation](https://warminboxes.com/skills/warm-rotation) — How do I make my inboxes last longer?

- [Cold Email Playbook](https://warminboxes.com/skills/cold-email-playbook) — Why did my replies drop, and what do I do?

- [Infrastructure API](https://warminboxes.com/skills/infrastructure-api) — How do I connect my WarmInboxes account to Claude?