Machine-wash in reverse, in cold water (30 degrees C max), and with similar colours.
Hang-dry in shade would be great to reduce the ironing effort.
Due to the nature of the fabric, ironing is not often required.
If it is an oil based stain, use a small amount of washing up detergent, gently massaging the outer perimeter of the stain, working your way into the centre of the stain. This stops the stain from dispersing further. Rinse thoroughly and then wash the complete shirt as normal. If it is a water based stain, a normal soak, followed by a complete wash should be sufficient.