too many emails in mail osx

[Brian Yennie]

Working off of this, you can create filters that funnel everything to 
folders, and then on top of those some more disabled filters which 
funnel to archived folders.
When you want to archive, turn on the extra filters, select all in any 
folder, and use "Message->Apply Rules to Selection".

I'm sure there are more elegant ways, but this works for me with about 
10,000 archived messages...

> ANother ideas is you can create subfolders in Mail.app. Drag messages 
> into the subfolders. You could make a folder for every 6 months of 
> archives, or something. That would make searching more manageable.