AWeber cannot be used for the purpose of cleaning your mailing list. However, this does not mean that we do not help you to maintain your list of subscribers.
The purpose of AWeber is to help you build, maintain, track, and keep in contact with your subscribers through your email campaign. Our service can be used to help you manage bounces, unsubscribes, and inactive subscribers over the lifetime of your mailing list. However, if you are trying to import a list into your account that is of poor quality, there is a good chance that the import may be rejected.
Does AWeber Clean Imported Lists?
When lists of new subscribers are imported into your account they are screened against a large database we have of addresses and domains that are currently known to be undeliverable. These do not account for all invalid addresses that might be present, rather they are simply the most obvious examples. When an import comes in and contains addresses like that we will use that information as an indicator of how well the list was maintained previously. If we detect enough of those undeliverable/bounced email addresses then we take that as a sign that the list has not been maintained/updated and may reject your import based off of that.
Aweber will not identify/remove the undeliverable email addresses for you, as that would defeat the purpose of making sure the submitted list was well maintained previously. By only deleting the most obvious undeliverable email addresses it is not necessarily cleaning the list of all undeliverable email addresses.
Why Should I Import A Clean List?
One of the obstacles in email marketing is that ISPs monitor very carefully for bounced messages or mailings sent to older or dormant addresses. If they notice activity like that, it can cause them to restrict your sending, and this can do serious damage to your ability to run your campaign. It's for this reason that we may reject an import that contains enough undeliverable subscribers, simply to avoid the damage to your campaign and subsequently, the entire system.
While there certainly are services out there that are dedicated to list cleaning, we do not necessarily recommend them and advise you to only use them at your own discretion. As far as we have seen, there is no service that can completely clean your list of undeliverable/invalid email addresses.