Select the object with the color you want to save and then pass your cursor over the swatches panel. The cursor will change to a paint bucket icon. Click in a blanck spot of the swatches panel to drop the color. That's it. The color will remain there until you delete it by reloading the swatches palette via the swatches panel menu. If you like, you can clear the palette and create your own. You can then export it and reload it whenever you wish.
thankyou so much Linda. That was really helpful