How to delete Elasticache Default Cache Parameter Groups?

Question

Using AWS Resource Explorer, I found regions like Soeul (AP-northeast-2) that have dozens of Elasticache Cache Parameter Groups.   I have not used any elastic cache resources in this region before. There are no existing elasticache clusters or resources besides Cache Paramater Groups.

I would like to clean up all AWS resources in regions that are not in use.

Here is what I tried. 
* I tried deleting from console -- but delete is disabled
* I tried deleting from AWS CLI (see below), but I receive `InvalidParameterValue` / 400 error.

```

aws --profile=my-admin-role --region=ap-northeast-2 elasticache delete-cache-parameter-group \
--cache-parameter-group-name="default.memcached1.4"

An error occurred (InvalidParameterValue) when calling the DeleteCacheParameterGroup operation: The parameter CacheParameterGroupName is not a valid identifier. Identifiers must begin with a letter; must contain only ASCII letters, digits, and hyphens; and must not end with a hyphen or contain two consecutive hyphens.
 ✘  tonymet@tony-beelink-2023b  ~/.aws  aws help
```

Riku_Kobayashi · Answer

Hello.

The default ElastiCache parameter group created by AWS cannot be deleted.  
Therefore, it is normal that it cannot be deleted using either the management console or the AWS CLI.  
https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/ParameterGroups.Management.html  
> You cannot modify or delete the default parameter groups. If you need custom parameter values, you must create a custom parameter group.

How to delete Elasticache Default Cache Parameter Groups?

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