The phenomenon of parthenogenesis was discovered in the 18th cent. by Charles Bonnet. In 1900, Jacques Loeb accomplished the first clear case of artificial parthenogenesis when he pricked unfertilized frog eggs with a needle and found that in some cases normal embryonic development ensued. Artificial parthenogenesis has since been achieved in almost all major groups of animals, although it usually results in incomplete and abnormal development. Numerous mechanical and chemical agents have been used to stimulate unfertilized eggs.
is this what you are talking about? i have sharks and insects "cloning" themselves but i have never heard of iguanas doing this.
There's nothing you can do to the eggs to "make" them fertile. As for parthenogenesis, it's possible in some reptiles, but, AFAIK, has not been documented in iguanas and is extremely unlikely either way.
Suffice to say, it's just an infertile clutch, nothing more, nothing less. Many female iguanas will lay infertile eggs every (or almost every) season for no real reason, just like with beardies and many other reptiles.