Strategies for a big personal inbox (ideas, not emails)

This is probably a life problem, not a GTD problem... I'm still struggling with my (GTD) inbox.

My work email inbox is massive, but I've wrestled it under control with lots of automation and filtering.

My personal inbox however is out of control. I spend 3 - 4 hours a week sifting my GTD inbox (out of maybe 5 hrs to devote to GTD).

90% of my GTD inbox is my own ideas for new projects, ideas about existing projects, things to read, look at etc.

Other than stop capturing, what options are there for me?

1. Filter: Like I do with work emails? e.g. stop exposing myself to "inspiration" - get off the internet - avoid caffiene (caffiene makes ideas sometimes)?

2. Automate: Like I do with work emails? e.g. set up some software to move obviously project-related (tagged?) ideas and materials to the relevant project reference area?

3. Something else?

I'd love to hear your techniques?