I have a highlighter and a marker I have been able to empty out and refill with bleach, paintbrushes, and a cool mix thing I ran across where they have caps like pens, brushes for the tips and they are fillable for water or watercolor paints and I use bleach instead!
I think OP said highlighter maybe?
I have a highlighter and a marker I have been able to empty out and refill with bleach, paintbrushes, and a cool mix thing I ran across where they have caps like pens, brushes for the tips and they are fillable for water or watercolor paints and I use bleach instead!