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MailCull

MailCull blog: field notes on email deliverability and list quality

2026 9 of 9

Re-Engagement Campaigns: Winning Back Inactive Subscribers Without Wrecking Deliverability

You are about to mail the riskiest segment you own. Do it in this order.

September 27, 20266 mindeliverability

You Inherited a Purchased Email List. Now What?

Verification tells you the addresses work. It cannot tell you that you may mail them.

September 24, 20266 minlist-cleaning

Email List Decay: How Fast Your List Rots and What to Do About It

Roughly 2% a month, but the range is wide and the drivers are predictable.

September 12, 20266 minlist-hygiene

Bulk Sender Requirements in 2026: What Gmail, Yahoo and Microsoft Now Enforce

The 0.3% spam ceiling is the rule everyone quotes. The list-hygiene requirement is the one that catches people.

September 9, 20266 mindeliverability

The Real Cost of a Dirty Email List (With the Actual Math)

Four costs, three of them invisible. Here is the arithmetic.

September 6, 20266 minlist-cleaning

Why Are My Emails Bouncing? A Diagnostic Walkthrough

The bounce report has the answer. You just need to read the codes.

September 3, 20267 minbounce-rate

What Actually Happens When You Send to an Invalid Email Address

One bad address doesn't just bounce. It nudges every subsequent send a little closer to the spam folder.

August 25, 20267 mindeliverability

How to Reduce Your Email Bounce Rate: The Complete 2026 Guide

Bounce rate is a single number with five different causes underneath. Here's how to find yours and fix the right one.

August 13, 20268 minbounce-rate

Clean Your Email List Before Cold Outreach: A Non-Negotiable Step

Cold outreach gives you almost no room for list-quality mistakes. Here is the bounce math, the sender caps, and the inbox-rotation risk that make pre-send verification non-negotiable.

July 14, 20266 mincold-outreach
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