Does anyone know how to edit (add or remove) colors from an existing ase file?
Which version of Illustrator are you using?
You may open the .ase library in Illustrator, transfer all swatches to the main Swatches palette, add or remove swatches there and then save it as an .ase file.
Adobe 2019. So there's no way to edit the actual ase file.... just create a new one?
You may try to open and modify the .ase file in an appropriate text editor, but I'm pretty sure it will take more time and probably cause more trouble than taking the reliable route I described above.
thank you 🙂