Air-layering certainly is a good option and it should be very safe
If you desire more plants you could try taking stem cuttings around 3-4 inches long. It's important they aren't to short. Remove all of the leaves from these pieces if there are any present. Place the pieces laying on their side, just half buried in a lightly moist rooting mix. Put these in a mini greenhouse or similar as per usual. This will take a long time if I recall correctly. It should look like this image I found on the net: http://gardentia.net/?attachme...
Be sure to ventilate the greenhouse every day.
That said it was a very
long time ago since I done this, but it should have a reasonable success rate, perhaps also depending on the cultivar, as some will be easier to succeed with than others. Good luck!