You'll want to clean up after you are done in the account have shared the AMI and no longer have a need for the replicated instances:
Post instance WIGs ingestion:
Cutover instance: At a minimum, stop or terminate this instance, after the work has been completed, via the AWS console
Pre-Ingestion AMI backups: Remove once the instance has been ingested and the on-premise instance terminated
AMS-ingested instances: Turn off the stack or terminate once the AMI has been shared
AMS-ingested AMIs: Delete once sharing with the destination account is completed
End of migration clean up: Document the resources deployed through Developer mode to ensure clean-up happens on regular basis, for example:
Security groups
Resources created via Cloud-formation
Network ACK
Subnet
VPC
Route Table
Roles
Users and accounts
