Does anyone know why some RGB swatches cannot be deleted, I've searched character styles, paragraph styles, objects, characters, fills and strokes and cannot find where the swatch is used, but is not selected with 'select all unused', it is uneditable. Any ideas what causes this?
Perhaps you have some placed EPS or PDF that defines some colors?
If it's not a placed link like Dov suggests and you still can't delete it, this trick works for me:
Make a new object that uses the swatch, make a new document, cut the swatch into it, save that document, place that new document in the original, delete it, then you should be able to delete the swatch. I've never tried it with multiple swatches at a time though.