public static void DeleteAccessKeysForUser(AmazonIdentityManagementServiceClient client, string username)
{
ListAccessKeysResponse response = client.ListAccessKeysAsync(new ListAccessKeysRequest() { UserName = username }).Result;
foreach (AccessKeyMetadata akm in response.AccessKeyMetadata)
{
client.DeleteAccessKeyAsync(new DeleteAccessKeyRequest() { UserName = username, AccessKeyId = akm.AccessKeyId }).Wait();
}
}