Go through your fabric stash. If you do applique or make scrap quilts keep 1/4 yd of each fabric. Put the rest in a box or clean trash bag.
Keep a few fabrics for background and/or backing and binding.
Take the rest to your local quilt guild for their charity quilts. Or give it to a local Prayers and Squares Ministry (many churches have them).
My criteria....look at each piece of fabric....it is either:
loved the fabric when I bought it, no longer love it, will never use it in a quilt....goes into charity bag.
OR: If you say loved the fabric when I bought it, still love it and will really use it in a quilt, keep it.
I once gave our local guild 26 plastic trash bags of fabric. It was sooooo freeing and you get a tax donation slip :).