Destroy missing upload topic

I would like to take bulk action to delete all post with missing upload image:

> rake posts:missing_uploads
   70782 post uploads are missing.
   61037 uploads are missing.
   23249 of 216049 posts are affected.
> PostCustomField.where(name: Post::MISSING_UPLOADS).count
===> 23249

So I decide to delete all of them with below code on rails c

> rails c
>  PostCustomField.where(name: Post::MISSING_UPLOADS).find_each do |post|
>, post).destroy
>    end

But no luck with error show as below:

NoMethodError: undefined method `topic' for #<PostCustomField:0x000055dd7425e160>
from /var/www/discourse/vendor/bundle/ruby/2.7.0/gems/activemodel- `method_missing'

I would like to looking for some help in this case to bulk destroy missing upload topic

Thank you,