Email & retention
How do you email an old list without wrecking your deliverability?
The short answer
Clean the list first, then send to it in batches of a few hundred, starting with your freshest leads. Check opens and bounces after each batch before you step back to older contacts, and stop when a batch is dead. Going from a handful of emails a week to thousands overnight is one of the quickest ways to burn your sending domain.
Why can’t you just send to everyone?
Because old lists bounce. Plenty of those addresses are dead or were never real in the first place. The older the emails, the higher the chance of getting lots of bounces, and too many bounces in one send can get your domain flagged for spam.
Volume makes it worse. If your domain has been sending ten or fifteen emails a week, jumping to a few thousand in one go is quite risky. Doing that to an aged list with no sending history is about the fastest way I know to wreck your deliverability.
I had this exact conversation with a business sitting on a CRM full of historical leads that had barely been emailed. They had a launch coming up and wanted to tell everyone. My answer was that if we sent to that whole database, we’d completely nuke the domain.
Burn your domain and every tool you send from stops working. It’s recoverable, but it’s a mission. Far better to warm up slowly than to dig yourself out.
How do you clean an old email list?
Run the whole thing through a list-cleaning tool before you send a single email. It strips out the fake and dead addresses that cause bounces. Then cull anything that’s still obviously junk.
On that call I kept it simple. We just need to do some cleaning of the database first, so we filter out any of the dud leads before we send any emails. Skip this step and every batch that follows is a gamble.
Which contacts should you email first?
Your freshest leads. Draw a line by lead age and work backwards from the newest. Someone who signed up a couple of months ago will still recognise you, so they’re more likely to open and less likely to bounce. Someone from years back might not remember you at all.
This is the order I’d follow:
- Clean the list.
- Split it into batches by how long ago each lead came in.
- Start with leads from the last four to sixteen weeks.
- Send in groups of about 500 contacts at a time.
- Check the open rate and bounce rate on that batch.
- If they look healthy, step back to the next oldest batch and repeat.
- When a batch is completely dead, stop there.
That’s how we ran it on that lead list. We’d start with the newest leads, test how it goes, and then go a little bit older, and then a little bit older.
The last step is the one people skip. At some point you may hit a batch where nobody opens and plenty bounce. Leave everything past that line alone. Mailing it only puts at risk the domain you’ve just warmed up.
What should you actually send them?
Something personal and plain. These people haven’t heard from you in a long time, so a heavily designed promo out of nowhere is a hard sell.
If it’s a list of past customers, start with your best ones and look after them personally. Anyone who’s bought from you two or three times should get a personal email from the founder, and maybe a call or a text as well. Sell to them one to one. The next tier down gets lighter personal outreach. Everyone else goes into the batched sends.
Keep the emails mostly plain text with good copy. If you want to show off the product, record a quick walkthrough on Loom. You don’t need a videographer. Loom videos are just a link you can include in an email. That’s the 80-20.
How fast can you ramp up once it’s working?
Slower than you’d like. Even once the batches are going well, don’t jump straight to a full calendar. If you go from zero emails to fifteen in thirty days on a dormant account, that just nukes it.
Add sends a bit at a time and watch your open rates as you go. If they hold, keep building. If they start sliding, ease off before you push any harder.