I am warning you this is an idea masacre. It's quite tough having to say goodbye to 900 out of 1000 ideas. But better now than after you spent years trying to realise a "dead horse" project.
I will give you three methods to reduce your set of ideas to 100. Everytime you use a new method you should approximately halfe the amount of ideas. The methods are quite crude - that's necessarry to keep momentum in the process.
"Kill your darling"? - No way! But be selective. Only work with ideas that you like and that has potential. The hardest thing is working on ideas that are not quite a success - nor a complete bummer. They can drain your energy and never reward you for the hardship.
"Be ware ... and be brutal."
Exercises and methods:
1. Going through the ideas fast.
2. Grouping ideas.