Messages will be deleted from trash after 30 days

Hello

I'm trying hard to stop getting so much junk/spam Mail on my iPad.

I understand that setting Rules for Mail should be done at the iCloud web level - that is, using Safari, logging in to my Mail, and setting up Rules, etc.

But I run into what seems a crazy situation because iCloud-Mail-Preferences tells me "Messages will be deleted from the trash after 30 days."

Here is what I am doing:

On my MacBook Pro, in Lion, using Safari, I go to Mail.

When I see spam in my Inbox, I drag it to Junk. (I also have set up as many Rules as I can trying to intercept the neverending flow).

Then I delete the mail in the junk folder.

Then I Empty Trash.

All of this is in my effort to stop getting all this same junk when I later use my iPad to access email.

BUT… in Mail on iCloud (using Safari) under Preferences, I have "Move deleted messages to: Trash." But below that it says "Messages will be deleted from the trash after 30 days."

How can I change that so when I delete something in Mail, on iCloud, then go to my iPad…it does not reappear there?

I'm far more accustomed to earlier Mac OS's, like Snow Leopard (which I still use on my Mac Pro) and where I could set preferences to delete trash on quitting Mail. And could set options for keeping or not keeping any messages on the server for so many days.

Any help, please.

*Under Products, below, I can't click both radio buttons for MBP and iPad, so I left it on MBP.

My iPad is the Mini, running v 6.1.3

The MacBook Pro is 10.7.5

(My Mac Pro is 10.6.8 - and yes, I do understand it is not able to fully interact with iCloud; I'm talking here about the MBP and the iPad Mini)

Thanks in advance.